Electrochemical fabrication method and apparatus for producing three-dimensional structures having improved surface finish

Abstract

An electrochemical fabrication process produces three-dimensional structures (e.g. components or devices) from a plurality of layers of deposited materials wherein the formation of at least some portions of some layers are produced by operations that remove material or condition selected surfaces of a deposited material. In some embodiments, removal or conditioning operations are varied between layers or between different portions of a layer such that different surface qualities are obtained. In other embodiments varying surface quality may be obtained without varying removal or conditioning operations but instead by relying on differential interaction between removal or conditioning operations and different materials encountered by these operations.

Description

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/364,261 filed Mar. 13, 2002 and U.S. Provisional Application No. 60/379,130, filed May 7, 2002 which are hereby incorporated herein by reference as if set forth in full herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to the formation of three-dimensional structures (e.g. components or devices) using electrochemical fabrication methods via a layer-by-layer build up of deposited materials where at least some layers are subjected to surface conditioning processes and wherein the surface conditioning processes are varied to yield varying surface finishes between different portions of a single layer or between different layers or portions of different layers.

BACKGROUND

[0003] A technique for forming three-dimensional structures (e.g. parts, components, devices, and the like) from a plurality of adhered layers was invented by Adam L. Cohen and is known as Electrochemical Fabrication as it uses various electrochemical methods in the fabrication of three-dimensional structures. It is being commercially pursued by MEMGen™ Corporation of Burbank, Calif. under the name EFAB™ This technique was described in U.S. Pat. No. 6,027,630, issued on Feb. 22, 2000. This electrochemical deposition technique allows the selective deposition of a material using a unique masking technique that involves the use of a mask that includes patterned conformable material on a support structure that is independent of the substrate onto which plating will occur. When desiring to perform an electrodeposition using the mask, the conformable portion of the mask is brought into contact with a substrate while in the presence of a plating solution such that the contact of the conformable portion of the mask to the substrate inhibits deposition at selected locations. For convenience, these masks might be generically called conformable contact masks; the masking technique may be generically called a conformable contact mask plating process. More specifically, in the terminology of MEMGen™ Corporation of Burbank, Calif. such masks have come to be known as INSTANT MASKS™ and the process known as INSTANT MASKING™ or INSTANT MASK™ plating. Selective depositions using conformable contact mask plating may be used to form single layers of material or may be used to form multi-layer structures. The teachings of the '630 patent are hereby incorporated herein by reference as if set forth in full herein. Since the filing of the patent application that led to the above noted patent, various papers about conformable contact mask plating (i.e. INSTANT MASKING) and electrochemical fabrication have been published:

[0004] 1. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will, “EFAB: Batch production of functional, fully-dense metal parts with micro-scale features”, Proc. 9th Solid Freeform Fabrication, The University of Texas at Austin, p161, Aug. 1998.

[0005] 2. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro Mechanical Systems Workshop, IEEE, p244, Jan 1999.

[0006] 3. A. Cohen, “3-D Micromachining by Electrochemical Fabrication”, Micromachine Devices, March 1999.

[0007] 4. G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P. Will, “EFAB: Rapid Desktop Manufacturing of True 3-D Microstructures”, Proc. 2nd International Conference on Integrated MicroNanotechnology for Space Applications, The Aerospace Co., Apr.1999.

[0008] 5. F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P. Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures using a Low-Cost Automated Batch Process”, 3rd International Workshop on High Aspect Ratio MicroStructure Technology (HARMST'99), June 1999.

[0009] 6. A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P. Will, “EFAB: Low-Cost, Automated Electrochemical Batch Fabrication of Arbitrary 3-D Microstructures”, Micromachining and Microfabrication Process Technology, SPIE 1999 Symposium on Micromachining and Microfabrication, September 1999.

[0010] 7. F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P. Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures using a Low-Cost Automated Batch Process”, MEMS Symposium, ASME 1999 International Mechanical Engineering Congress and Exposition, November, 1999.

[0011] 8. A. Cohen, “Electrochemical Fabrication (EFABTM)”, Chapter 19 of The MEMS Handbook, edited by Mohamed Gad-EI-Hak, CRC Press, 2002.

[0012] 9. “Microfabrication—Rapid Prototyping's Killer Application”, pages 1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June 1999.

[0013] The disclosures of these nine publications are hereby incorporated herein by reference as if set forth in full herein.

[0014] The electrochemical deposition process may be carried out in a number of different ways as set forth in the above patent and publications. In one form, this process involves the execution of three separate operations during the formation of each layer of the structure that is to be formed:

[0015] 1. Selectively depositing at least one material by electrodeposition upon one or more desired regions of a substrate.

[0016] 2. Then, blanket depositing at least one additional material by electrodeposition so that the additional deposit covers both the regions that were previously selectively deposited onto, and the regions of the substrate that did not receive any previously applied selective depositions.

[0017] 3. Finally, planarizing the materials deposited during the first and second operations to produce a smoothed surface of a first layer of desired thickness having at least one region containing the at least one material and at least one region containing at least the one additional material.

[0018] After formation of the first layer, one or more additional layers may be formed adjacent to the immediately preceding layer and adhered to the smoothed surface of that preceding layer. These additional layers are formed by repeating the first through third operations one or more times wherein the formation of each subsequent layer treats the previously formed layers and the initial substrate as a new and thickening substrate.

[0019] Once the formation of all layers has been completed, at least a portion of at least one of the materials deposited is generally removed by an etching process to expose or release the three-dimensional structure that was intended to be formed.

[0020] The preferred method of performing the selective electrodeposition involved in the first operation is by conformable contact mask plating. In this type of plating, one or more conformable contact (CC) masks are first formed. The CC masks include a support structure onto which a patterned conformable dielectric material is adhered or formed. The conformable material for each mask is shaped in accordance with a particular cross-section of material to be plated. At least one CC mask is needed for each unique cross-sectional pattern that is to be plated.

[0021] The support for a CC mask is typically a plate-like structure formed of a metal that is to be selectively electroplated and from which material to be plated will be dissolved. In this typical approach, the support will act as an anode in an electroplating process. In an alternative approach, the support may instead be a porous or otherwise perforated material through which deposition material will pass during an electroplating operation on its way from a distal anode to a deposition surface. In either approach, it is possible for CC masks to share a common support, i.e. the patterns of conformable dielectric material for plating multiple layers of material may be located in different areas of a single support structure. When a single support structure contains multiple plating patterns, the entire structure is referred to as the CC mask while the individual plating masks may be referred to as “submasks”. In the present application such a distinction will be made only when relevant to a specific point being made.

[0022] In preparation for performing the selective deposition of the first operation, the conformable portion of the CC mask is placed in registration with and pressed against a selected portion of the substrate (or onto a previously formed layer or onto a previously deposited portion of a layer) on which deposition is to occur. The pressing together of the CC mask and substrate occur in such a way that all openings, in the conformable portions of the CC mask contain plating solution. The conformable material of the CC mask that contacts the substrate acts as a barrier to electrodeposition while the openings in the CC mask that are filled with electroplating solution act as pathways for transferring material from an anode (e.g. the CC mask support) to the non-contacted portions of the substrate (which act as a cathode during the plating operation) when an appropriate potential and/or current are supplied.

[0023] An example of a CC mask and CC mask plating are shown in FIGS. 1(a)-1(c). FIG. 1(a) shows a side view of a CC mask 8 consisting of a conformable or deformable (e.g. elastomeric) insulator 10 patterned on an anode 12. The anode has two functions. FIG. 1(a) also depicts a substrate 6 separated from mask 8. One is as a supporting material for the patterned insulator 10 to maintain its integrity and alignment since the pattern may be topologically complex (e.g., involving isolated “islands” of insulator material). The other function is as an anode for the electroplating operation. CC mask plating selectively deposits material 22 onto a substrate 6 by simply pressing the insulator against the substrate then electrodepositing material through apertures 26a and 26b in the insulator as shown in FIG. 1 (b). After deposition, the CC mask is separated, preferably non-destructively, from the substrate 6 as shown in FIG. 1(c). The CC mask plating process is distinct from a “through-mask” plating process in that in a through-mask plating process the separation of the masking material from the substrate would occur destructively. As with through-mask plating, CC mask plating deposits material selectively and simultaneously over the entire layer. The plated region may consist of one or more isolated plating regions where these isolated plating regions may belong to a single structure that is being formed or may belong to multiple structures that are being formed simultaneously. In CC mask plating as individual masks are not intentionally destroyed in the removal process, they may be usable in multiple plating operations.

[0024] Another example of a CC mask and CC mask plating is shown in FIGS. 1(d)-1(f). FIG. 1(d) shows an anode 12′ separated from a mask 8′ that comprises a patterned conformable material 10′ and a support structure 20. FIG. 1(d) also depicts substrate 6 separated from the mask 8′. FIG. 1(e) illustrates the mask 8′ being brought into contact with the substrate 6. FIG. 1(f) illustrates the deposit 22′ that results from conducting a current from the anode 12′ to the substrate 6. FIG. 1(g) illustrates the deposit 22′ on substrate 6 after separation from mask 8′. In this example, an appropriate electrolyte is located between the substrate 6 and the anode 12′ and a current of ions coming from one or both of the solution and the anode are conducted through the opening in the mask to the substrate where material is deposited. This type of mask may be referred to as an anodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact (ACC) mask.

[0025] Unlike through-mask plating, CC mask plating allows CC masks to be formed completely separate from the fabrication of the substrate on which plating is to occur (e.g. separate from a three-dimensional (3D) structure that is being formed). CC masks may be formed in a variety of ways, for example, a photolithographic process may be used. All masks can be generated simultaneously, prior to structure fabrication rather than during it. This separation makes possible a simple, low-cost, automated, self-contained, and internally-clean “desktop factory” that can be installed almost anywhere to fabricate 3D structures, leaving any required clean room processes, such as photolithography to be performed by service bureaus or the like.

[0026] An example of the electrochemical fabrication process discussed above is illustrated in FIGS. 2(a)-2(f). These figures show that the process involves deposition of a first material 2 which is a sacrificial material and a second material 4 which is a structural material. The CC mask 8, in this example, includes a patterned conformable material (e.g. an elastomeric dielectric material) 10 and a support 12 which is made from deposition material 2. The conformal portion of the CC mask is pressed against substrate 6 with a plating solution 14 located within the openings 16 in the conformable material 10. An electric current, from power supply 18, is then passed through the plating solution 14 via (a) support 12 which doubles as an anode and (b) substrate 6 which doubles as a cathode. FIG. 2(a), illustrates that the passing of current causes material 2 within the plating solution and material 2 from the anode 12 to be selectively transferred to and plated on the cathode 6. After electroplating the first deposition material 2 onto the substrate 6 using CC mask 8, the CC mask 8 is removed as shown in FIG. 2(b). FIG. 2(c) depicts the second deposition material 4 as having been blanket-deposited (i.e. non-selectively deposited) over the previously deposited first deposition material 2 as well as over the other portions of the substrate 6. The blanket deposition occurs by electroplating from an anode (not shown), composed of the second material, through an appropriate plating solution (not shown), and to the cathode/substrate 6. The entire two-material layer is then planarized to achieve precise thickness and flatness as shown in FIG. 2(d). After repetition of this process for all layers, the multi-layer structure 20 formed of the second material 4 (i.e. structural material) is embedded in first material 2 (i.e. sacrificial material) as shown in FIG. 2(e). The embedded structure is etched to yield the desired device, i.e. structure 20, as shown in FIG. 2(f).

[0027] Various components of an exemplary manual electrochemical fabrication system 32 are shown in FIGS. 3(a)-3(c). The system 32 consists of several subsystems 34, 36, 38, and 40. The substrate holding subsystem 34 is depicted in the upper portions of each of FIGS. 3(a) to 3(c) and includes several components: (1) a carrier 48, (2) a metal substrate 6 onto which the layers are deposited, and (3) a linear slide 42 capable of moving the substrate 6 up and down relative to the carrier 48 in response to drive force from actuator 44. Subsystem 34 also includes an indicator 46 for measuring differences in vertical position of the substrate which may be used in setting or determining layer thicknesses and/or deposition thicknesses. The subsystem 34 further includes feet 68 for carrier 48 which can be precisely mounted on subsystem 36.

[0028] The CC mask subsystem 36 shown in the lower portion of FIG. 3(a) includes several components: (1) a CC mask 8 that is actually made up of a number of CC masks (i.e. submasks) that share a common support/anode 12, (2) precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on which the feet 68 of subsystem 34 can mount, and (5) a tank 58 for containing the electrolyte 16. Subsystems 34 and 36 also include appropriate electrical connections (not shown) for connecting to an appropriate power source for driving the CC masking process.

[0029] The blanket deposition subsystem 38 is shown in the lower portion of FIG. 3(b) and includes several components: (1) an anode 62, (2) an electrolyte tank 64 for holding plating solution 66, and (3) frame 74 on which the feet 68 of subsystem 34 may sit. Subsystem 38 also includes appropriate electrical connections (not shown) for connecting the anode to an appropriate power supply for driving the blanket deposition process.

[0030] The planarization subsystem 40 is shown in the lower portion of FIG. 3(c) and includes a lapping plate 52 and associated motion and control systems (not shown) for planarizing the depositions.

[0031] In addition to teaching the use of CC masks for electrodeposition purposes, the '630 patent also teaches that the CC masks may be placed against a substrate with the polarity of the voltage reversed and material may thereby be selectively removed from the substrate. It indicates that such removal processes can be used to selectively etch, engrave, and polish a substrate, e.g., a plaque.

[0032] The '630 patent provides various examples of useful planarization methods. These examples include mechanical (e.g., diamond lapping and silicon carbide lapping), chemical-mechanical, and non-mechanical (e.g., electrical discharge machining) planarization processes.

[0033] Further teachings of the '630 patent indicate that diamond lapping can be performed using a single grade of diamond abrasive, e.g., about 1-6 micron, or diamond abrasives of various grades. Lapping with different grades of abrasive can be performed using separate lapping plates, or in different regions of a single plate. For example, a coarse diamond abrasive can be applied to the outer region of a spinning circular lapping plate, and a fine diamond abrasive can be applied to the inner region. A removable circular wall can be provided between the inner and outer regions to increase segregation. The layer to be planarized first contacts the outer region of the plate, is then optionally rinsed to remove coarse abrasive, and then is moved to the inner region of the plate. The planarized surface can then be rinsed using a solution, e.g., water-based or electrolyte-based solution, to remove both abrasive and abraded particles from the planarized layer. The abrasive slurry preferably is easily removable, e.g., water-soluble. Layer thickness, planarity and smoothness can be monitored, e.g., using an optical encoder, wear resistant stops, and by mating the layer under a known pressure with a precision flat metal plate and measuring the resistance across the plate-layer junction.

[0034] The '630 patent further provides an examples of a preferred planarization processes. One includes allowing the work piece, i.e., the substrate having the layer to be planarized, to rotate within a “conditioning ring” on the lapping plate. Another involves lapping being performed by moving a workpiece around the surface of a lapping plate using the X/Y motion stages of the electroplating apparatus without rotating or releasing the workpiece.

[0035] A need remains for improved electrochemical fabrication methods and apparatus that provided needed surface quality while optimizing production time. A need also remains for improved electrochemical fabrication methods and apparatus that provide different surface quality for different regions of a structure that is being formed.

SUMMARY OF THE INVENTION

[0036] It is an object of certain aspects of the invention to provide an improved electrochemical fabrication process or apparatus that provides needed surface quality without wasting production time.

[0037] It is an object of certain aspects of the invention to provide an improved electrochemical fabrication process or apparatus that provides different surface qualities for different regions of a structure.

[0038] Other objects and advantages of various aspects of the invention will be apparent to those of skill in the art upon review of the teachings herein. The various aspects of the invention, set forth explicitly herein or otherwise ascertained from the teaching herein, may address any one of the above objects alone or in combination, or alternatively may not address any of the objects set forth above but instead address some other object of the invention ascertained from the teachings herein. It is not intended that each of these objects be addressed by any single aspect of the invention even though that may be the case with regard to some aspects.

[0039] In a first aspect of the invention an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, includes (A) supplying a plurality of preformed masks, wherein each mask includes a patterned conformable dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask includes a support structure that supports the patterned conformable dielectric material; (B) selectively depositing at least a portion of a layer onto the substrate, wherein the substrate may include previously deposited material; (C) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming includes repeating operation (B) a plurality of times; wherein at least a plurality of the selective depositing operations include (1) contacting the substrate and the conformable material of a selected preformed mask; (2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, wherein the anode includes a selected deposition material, and wherein the substrate functions as a cathode, such that the selected deposition material is deposited onto the substrate to form at least a portion of a layer; and (3) separating the selected preformed mask from the substrate; and (D) removing material deposited on at least one layer using a first removal process that includes one or more operations having one or more parameters; and (E) removing material deposited on at least one different layer using a second removal process that includes one or more operations having one or more parameters, wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter.

[0040] In a second aspect of the invention an electrochemical fabrication apparatus for producing a three-dimensional structure from a plurality of adhered layers, includes (A) a plurality of preformed masks, wherein each mask includes a patterned conformable dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask includes a support structure that supports the patterned conformable dielectric material; (B) means for selectively depositing at least a portion of a layer onto the substrate, wherein the substrate may include previously deposited material; (C) means for forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming includes repeating operation (B)a plurality of times; wherein the means for selectively depositing includes (1)means for contacting the substrate and the conformable material of a selected preformed mask; (2) means for conducting, in presence of a plating solution, an electric current through the at least one opening in the selected mask between an anode and the substrate, wherein the anode includes a selected deposition material, and wherein the substrate functions as a cathode, such that the selected deposition material is deposited onto the substrate to form at least a portion of a layer; and (3) means for separating the selected preformed mask from the substrate; and (D) means for removing material deposited on at least one layer using a first removal process that includes one or more operations having one or more parameters; and (E) means for removing material deposited on at least one different layer using a second removal process that includes one or more operations having one or more parameters, wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter.

[0041] In a third aspect of the invention an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers includes (A) selectively depositing at least a portion of a layer onto a substrate, wherein the substrate may include previously deposited material; (B) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer; (C) removing material deposited on at least one layer using a first removal process that includes one or more operations having one or more parameters; and (E) removing material deposited on at least one different layer using a second removal process that includes one or more operations having one or more parameters, wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter.

[0042] In a fourth aspect of the invention an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) forming at least a portion of a layer by either selectively depositing a material, to form portion of a layer, onto a substrate or by selectively etching into a previously deposited material that occupies at least a portion of a layer and then depositing a material into an opening formed by the selective etching, wherein the substrate may include previously deposited layers of material; (B) forming a plurality of layers such that subsequent layers are formed adjacent to and adhered to previously deposited layers; (C) finishing a surface of at least a portion of one or more materials deposited on at least one layer using a first process that includes one or more operations having one or more parameters; and (E) finishing a surface of at least a portion of one or more materials deposited on the at least one layer using a second process that includes one or more operations having one or more parameters, wherein the portions subject to the first and second processes are not identical and wherein the first process differs from the second process by inclusion of at least one different operation, removal of at least one operation, or use of at least one different parameter value.

[0043] In a fifth aspect of the invention an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) forming at least a portion of a layer by either selectively depositing a material, to form portion of a layer, onto a substrate or by selectively etching into a previously deposited material that occupies at least a portion of a layer and then depositing a material into an opening formed by the selective etching, wherein the substrate may include previously deposited layers of material; (B) forming a plurality of layers such that subsequent layers are formed adjacent to and adhered to previously deposited layers; (C) finishing a surface of at least a portion of one or more materials deposited on at least one layer using a first process that includes one or more operations having one or more parameters; and (E) finishing a surface of at least a portion of one or more materials deposited on at least one different layer using a second process that includes one or more operations having one or more parameters, wherein the first process differs from the second process by inclusion of at least one different operation, removal of at least one operation, or use of at least one different parameter value.

[0044] Further aspects of the invention will be understood by those of skill in the art upon reviewing the teachings herein. Other aspects of the invention may involve combinations of the above noted aspects of the invention. These other aspects of the invention may provide various combinations of the aspects presented above as well as provide other configurations, structures, functional relationships, and processes that have not been specifically set forth above.

[0045] In some embodiments, electrochemical fabrication processes produce one or more three-dimensional structures (e.g. components or devices) from a plurality of layers of deposited materials wherein the formation of at least some portions of some layers are produced by operations that remove material, redistribute, condition, or otherwise finish selected surfaces of a deposited material. In some embodiments, removal, redistribution, conditioning, or finishing operations are varied between layers or between different portions of a layer such that different surface qualities are obtained. In other embodiments varying surface quality may be obtained without varying selected removal, redistribution or finishing operations or parameters but instead by relying on differential interaction between removal or conditioning operations and different materials encountered by these operations.

[0046] In some embodiments a finishing process (e.g. removal or conditioning process) on a 1st layer differs from a removal or conditioning process on a 2nd layer. In some more focused embodiments the finishing process used on a 1st layer includes an operation not used in the finishing process used on a 2nd layer. In some other more focused embodiments, the finishing process on a 2nd layer includes an operation not used in the process on the 1st layer. In some other embodiments the finishing process on the 1st layer includes a parameter which is different from a parameter used in the process on the 2nd layer.

[0047] In some embodiments a finishing process (e.g. removal or conditioning process) used on a 1st portion of a layer differs from the finishing process used on a 2nd portion of the layer. In some more focused embodiments, the finishing process used on the 1st portion includes an operation not used in the finishing process used on the 2nd portion. In some more focused embodiments, the finishing process used on the 2nd portion includes an operation not used in the finishing process used on the 1st portion. In some other embodiments, the finishing process used on the 1st portion includes a parameter which is different from a parameter used in the finishing process used on the 2nd portion.

[0048] In some embodiments a selected finishing process (e.g. removal or conditioning process) is used only a portion of a layer. In some more focused embodiments the process is limited to operating on one or more selected materials. In some more focused embodiments the process is limited to operating on one or more selected portions of one or more selected materials. In some other more focused embodiments, the process is limited so as not to operate on one or more selected portions of one or more selected materials. In some additional embodiments a mask having a pattern of openings corresponding to a pattern of a selected material forming a portion of the layer is use to define surface on which the process will operate. In some further embodiments a mask having a pattern of openings corresponding to non-outward facing surface of a selected material forming a portion of the layer is used to define the surface on which the process will operate

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIGS. 1(a)-1(c) schematically depict a side view of various stages of a CC mask plating process, while FIGS. 1(d)-(g) depict a side view of various stages of a CC mask plating process using a different type of CC mask.

[0050] FIGS. 2(a)-2(f) schematically depict side views of various stages of an electrochemical fabrication process as applied to the formation of a particular structure where a sacrificial material is selectively deposited while a structural material is blanket deposited.

[0051] FIGS. 3(a)-3(c) schematically depict side views of various example subassemblies that may be used in manually implementing the electrochemical fabrication method depicted in FIGS. 2(a)-2(f).

[0052] FIGS. 4(a)-4(g) depict the formation of a 1st layer of a structure using through mask plating where the blanket deposition of a second material overlays both the openings between deposition locations of a 1st material and the first material itself.

[0053] FIG. 5 depicts a flowchart of the generalized process of the instant invention.

[0054] FIGS. 6(a) and 6(b) depict a CAD design of a scanning micro-mirror and an electrochemically fabricated structure according to that design, respectively.

[0055] FIGS. 7(a)-7(h) set forth a side view of a six layer structure as well as top views of each layer of that structure.

[0056] FIGS. 8(a)-8(h) illustrate a side view and top views of the structure of FIGS. 7(a)-7(h) where each of the four distinct regions for each layer are illustrated.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0057] FIGS. 1(a)-1(g), 2(a)-2(f), and 3(a)-3(c) illustrate various features of Electrochemical Fabrication that are known. Other electrochemical fabrication techniques are set forth in the '630 patent referenced above, in the various previously incorporated publications, in patent applications incorporated herein by reference, still others may be derived from combinations of various approaches described in these publications, patents, and applications, or are otherwise known or ascertainable by those of skill in the art. All of these techniques may be combined with those of the present invention to yield enhanced embodiments.

[0058] FIGS. 4(a)-4(f) illustrate various stages in the formation of a single layer of a multi-layer fabrication process where a second metal is deposited on a first metal as well as in openings in the first metal where its deposition forms part of the layer. In FIG. 4(a), a side view of a substrate 82 is shown, onto which patternable photoresist 84 is cast as shown in FIG. 4(b). In FIG. 4(c), a pattern of resist is shown that results from the curing, exposing, and developing of the resist. The patterning of the photoresist 84 results in openings or apertures 92(a)-92(c) extending from a surface 86 of the photoresist through the thickness of the photoresist to surface 88 of the substrate 82. In FIG. 4(d), a metal 94 (e.g. nickel) is shown as having been electroplated into the openings 92(a)-92(c). In FIG. 4(e), the photoresist has been removed (i.e. chemically stripped) from the substrate to expose regions of the substrate 82 which are not covered with the first metal 94. In FIG. 4(f), a second metal 96 (e.g., silver) is shown as having been blanket electroplated over the entire exposed portions of the substrate 82 (which is conductive) and over the first metal 94 (which is also conductive). FIG. 4(g) depicts the completed first layer of the structure which has resulted from the planarization of the first and second metals down to a height that exposes the first metal.

[0059] In some preferred embodiments of the invention electrochemical fabrication processes or apparatus are provided that include enhanced removal or finishing processes and apparatus. In particular the enhanced removal or finishing processes involve use of one or more different removal of finishing operations and/or one or more different removal or finishing parameters on at least two different layers. The use of one process may allow faster, or otherwise preferred, removal of finishing operations to occur for selected layers (e.g. when surface quality is not critical) while a slower process may be used, or an otherwise less preferred removal or finishing process, when surface quality is more critical. Thus, the use of different definable removal processes allows process optimization to occur.

[0060] In other embodiments different finishing operations may be used on different parts of a single layer or on different layers simply to obtain a desired difference in surface finish regardless of the overall processing time.

[0061] A flow chart depicting the general electrochemical fabrication process for some embodiments of the invention is depicted in FIG. 4. Element 102 depicts the beginning of the process while element 104 sets the layer number variable “i”, to a value of one. Decision block 106 inquires as to whether or not the layer number variable “i” has exceeded the total number of layers “N” in the structure being formed. If so the process ends with element 8. Assuming the variable “I” has not exceeded the total number of layers “N”, element 112 sets the deposition number variable “j” for layer “i” to a value of one. Element 114 calls for the deposition of the material associated with deposition number “j” for layer “i”. Element 116 increments the deposition number by one. Element 118 inquires as to whether or not the deposition number exceeds the maximum number of depositions “M” associated with layer “i”. If not, the process loops back to element 114 and the next deposition for layer “i” is performed. If “yes”, the process moves forward to element 122 where the finishing process (e.g. removal, redistribution, or conditioning process) operation variable “k” is set to a value of 1. Next the process moves to element 124 where the finishing process “k” is performed for layer “i”. The finishing process “k” associated with any given layer “i” may or may not exist. If it exists it may involve an identical operation or parameters that were used on other layers, it may involve a different operation from that used on one or more layers, or it may involve a similar operation used on other layers but with different associated parameters. After performance of removal process “k’ for layer “i”, the process proceeds to element 126 where an inquiry is made as to whether or not the value of “k” exceeds the maximum number of finishing operations “P” associated with layer “i”. If it does not, “k” is incremented by one and the process loops back to element 124 for performing the next removal operation for layer “i”. If “k” does equal “P”, the layer value “i” is incremented by 1 as indicated by element 132 and the process loops back to element 106. The value of “N”, the value of “M” for each layer “i”, the value of “P” for each layer “i”, the deposition processes associated with variable “j” for each layer “i”, and the finishing processes (i.e. operations and parameters) associated with variable “k” for each layer “i” can be held in the mind of an operator when a manual fabrication process is being used or they may be set in a look up table, determined or specified via a calculation, or otherwise determined and specified for use by an automated apparatus.

[0062] In some preferred embodiments of the present invention either the value of variable “k” is different between at least two layers and/or the operations or parameters associated with a given value of “k” for at least two different layers are different.

[0063] For example on one layer where surface finish is not critical, a single relatively course abrasive may be used in a single lapping process to remove material and planarize the layer whereas on a different layer two or more lapping processes may be used where progressively finer abrasives may be used to yield a smoother surface than would be obtained in the single removal operation. In an alternative process, a single lapping operation may be used on two different layers but one of the layers may additionally involve a buffing process or a polishing process such as CMP. In a further alternative, lapping or CMP may be used on two different layers but the parameters under which the operations operate may be changed.

[0064] In certain embodiments it may be desirable to use a finer abrasive to bring the layer to a desired level and then use a courser abrasive for a short period of time to roughen the surface without significantly changing its effective surface level. More generally, in some circumstances operations and parameters may be chosen so that certain layers are provided with a higher degree of smoothness while in other circumstances, operations and parameters are chosen to provide a course surface without significantly causing the level or height of the material to deviate from a desired level or height.

[0065] If a mirror like surface were desired for a given layer, more time or cost could be spent on the finishing operation (e.g. planarization operation and polishing operation) for that specific layer while allowing all other layers to undergo a faster or otherwise more acceptable process. The layer or layers that undergo a more rigorous, difficult, costly, or time consuming removal process may include the last layer of the structure, an initial layer of the structure, or may be limited to one or more intermediate layers.

[0066] If at least two different materials are being used in the deposition process, e.g. at least one sacrificial material and at least one structural material, then surface quality may be imparted either directly or indirectly by the finishing process. If the desired surface (i.e. the surface that is to have the desired attributes) is one that is being operated on by the removal process (e.g. planarized), the removal process imparts the quality to the surface directly and if the surface is associated with layer “i” then the removal operations are performed on layer “i”. If on the other hand, the desired surface is not one that is being planarized, then the quality of it is being imparted from the surface on which it was formed or will be formed. In this latter case, if the surface for which the particular quality is being sought is associated with layer “i” then it is layer “i-1”that must receive the specialized removal process. In other words if a structure is being formed by stacking layers one on top of the other, it is the up-facing surface of each layer that undergoes removal, it is the upper surfaces that obtain their surface qualities directly form the removal operations whereas the down-facing surfaces pick up their surface qualities as a result of the surface quality that was achieved on the previously formed layer. If the layers are being added below previously formed layers then rolls of the up-facing and down-facing surfaces are reversed.

[0067] In other embodiments, finishing may be performed at least in part using etchants that may be substantially non-selective with respect to their ability to etch materials being used in the formation of the structure or they may offer a significant level of selectivity for enhanced etching of one material relative to another. In still other embodiments electrochemical etching or polishing may be used during some or all finishing operations. In still other embodiments, finishing operations may involve a combined use of one or more of etchants, mechanical operations grinding or polishing operations, application of electrical currents or potentials, and the like.

[0068] The CAD design of a scanning micro-mirror device that can benefit from various embodiments of the invention is depicted in FIG. 6(a) while a mirror formed from that CAD file using electrochemical fabrication is shown in FIG. 6(b). The quality of the formed mirror and particularly the surface quality of the upper surface of the reflective portion 200 of the mirror may benefit from the enhanced fabrication techniques of various embodiments of the present invention. In these embodiments, the layer containing the upper surface of the mirror may undergo polishing operations which are not performed on other layers of the structure which can produce a mirror of desired reflectivity while not hindering the overall build process with such a high level of polishing on each layer.

[0069] In some embodiments, the selective application of specialized surface finishing may provide not only smoother surfaces when desired but also rougher surfaces or surfaces with other qualities when appropriate. For example, in some applications adhesion between successive layers may be enhanced by roughening the surface prior to deposition of the structural material associated with the next layer. In still other embodiments, significantly roughing or otherwise treating the surface may decrease undesired spectral reflections from that surface. For example in FIG. 6(b) it may be desirable to roughen or otherwise treat surfaces 202, 204, 206, 208, 210 and 212 to decrease such reflections. If one or more of these additional surfaces exist on the same layer where other finishing processes are desired (such as for surfaces 200, 204, 206, 208 and 210) it may be necessary to selectively performed the two or more finishing processes independent of one another. Alternatively, it may be possible to perform a first finishing process in a blanket manner with the subsequent processes formed in selective manners where the result of the first finishing process is simply the starting point for the subsequent operations. Of course, those of skill in the art will understand that other levels of processing selectivity or processing order are possible. For example, if a first selectively applied finishing process creates a great disparity between surface finishes of two distinct regions then a common blanket finishing operation may be used which still leaves a desired level of disparity between relevant attributes of the distinct regions. As a further example, after an initial planarization operation bring a given layer to a desired level and to a desired surface finish, a thin blank deposition or selective deposition of a desired coating material may be made, after which additional selective or blanket finishing operations may be used to take the entire surface or a portion of the surface to a final finished state.

[0070] In some embodiments it may be desirable to select, or tailor, the surface finish associated with a given portion of a layer depending on how that portion relates to the presence or lack of presence of structural material in the same area on a subsequent layer that is to be formed. In other embodiments, similar consideration of sacrificial materials may be used.

[0071] In some embodiments a single structural material will be used and that structural material will typically overlay at least in part, structural material deposited on a previous layer or structural material to be deposited on a subsequent layer. In these embodiments, structural material on each portion of a layer may be classified into one of four categories: (1) up facing, (2) down facing, (3) both up facing and down facing, and (4) continuing. An up facing portion of structural material on a given layer is that portion of the structural material that is not bounded by structural material that is associated with the next higher layer level. A down facing region of structural material on a given layer is that portion of the structural material that is not bounded from below by structural material located on the layer that is located immediately below the given layer. A portion of structural material defined as both up facing and down facing is not bounded from above or bounded from below by structural material that exists on the next higher layer or on the next lower layer. Finally, a portion of structural material located on a given layer that is bounded from below and bounded from above by structural material on the immediately preceding and exceeding layers is a continuing region.

[0072] In other embodiments layers need not be stacked along a vertical axis and thus these terms could either be defined for a different build orientation or alternatively they may simply be reinterpreted in an appropriate way. In embodiments where more than one structural material is used and/or more than one sacrificial material is used, additional or alternative distinct regions may be defined as necessary. In still other embodiments where sensitivity to certain structural features is critical, alternative or added regions may be defined. In still other embodiments where boundary effects between distinct regions, or other issues, make it desirable to define regions which are slightly larger or smaller than what is ascertainable from layer to layer comparisons alone, offset boundaries may be defined using erosion techniques or expansion techniques

[0073] FIGS. 7(a)-7(h) set forth a side view of a six layer structure as well as top views of each layer of that structure. FIGS. 7(a) depicts a side view of a six layer structure that includes layer portions that are definable in each of the four distinct categories noted above. For simplicity sake, the structure is assumed to be formed by stacking layers on top of one another starting with the first layer 301 formed on top of a substrate 300 followed by layers 302 to 306. Each layer comprises a portion that is formed of structural material 314 and a portion formed from a sacrificial material 316. A top view of the substrate 300 is shown is FIG. 7(b). The regions of structural material on layer 301 are shown in FIG. 7(c) relative to an outline 310 of the substrate. FIGS. 7(d)-7(h) show structural material associated with layers 302 to 306, respectively, relative to an outline 310 of substrate 300.

[0074] FIGS. 8(a)-8(h) illustrate a side view and top views of the structure of FIGS. 7(a)-7(h) where each of the four distinct regions for each layer are illustrated. FIG. 8(a) shows that a structure 308 is formed on a substrate 300 from layers 301 to layers 306. FIG. 8(a) also indicates that different portions of each layer can be classified into the different regions discussed above (where like regions are designated with like fill patterns). It can be seen that continuing regions 322 exist on some layers, regions that are both up facing and down facing 324 exist on some layers, regions that are down facing only 326 exist on some layers, and regions that are up facing only 328 exist on some layers. FIGS. 8(b)-8(h) illustrate top views of the substrate and each of layers 301 through 306, respectively, where distinct regions 322, 324, 326, and 328 are shown with fill patterns similar to those illustrated in FIG. 8(a).

[0075] The recognition of distinct portions (or regions) of layers may be used in tailoring finishing processes that may be used in achieving desired surface finishes for each portion of each layer. In some alternative embodiments, if desired, sacrificial material may also receive similar designations which may be used for determining additional or alternative surface finishing processes that may be used.

[0076] Once the distinct regions of each layer are determined, an associated desired surface quality parameter may be associated with each region. From the combined surface quality parameters associated with each layer appropriate surface finishing or treatment processes may be proposed and an order for performance proposed. From an analysis of the proposed processes and order, conflicts may be determined and either removed by process or order modifications or alternatively by deciding to use fall back or compromise finishing processes.

[0077] In some embodiments where structures will be formed by stacking layers one above the other, it may be appropriate to associate portions of a next layer (n+1) that are down-facing with the previous layer (n) so that appropriate finishing operations may be used on at least portions of the sacrificial material so that those portions have appropriate surface finish after forming the previous layer (n) which will be used in setting the surface quality of the down-facing features of structural material on the next layer (n+1). In embodiments with other build orientations (e.g. subsequent layers formed below previously formed layers) other appropriate association may be made.

[0078] As an example of how different surface finishes may be applied to a single layer one may consider layer 304 of FIG. 8(f). In this layer it may be seen that a portion of the structural material is continuing 322 and a portion is up-facing 328 or 324. If it is desired that up facing surfaces have a relatively smooth surface finish and that non-up-facing regions may have an alternative surface finish (e.g. one which is formed faster or one which is intentionally roughened up to, for example, enhance adhesion between layers), the entire layer may be planarized or polished to the extent desired to obtain the surface finish to be associated with up-facing features (assuming any exist on the layer being considered) then a contact mask or other mask may be placed against the resulting surface. The solid portions of the mask may be pressed against the portion of the surface(s) that are to retain the desired “up-facing” finish and the openings in the mask may be located over those portions of the surface(s) that are intended to have a different finish (e.g. rougher finish). The exposed surface(s) may be treated with an appropriate chemical etch, electrochemical etch, reactive or inactive material bombardment, radiation bombardment, or the like which is intended to produce the desired surface finish. After processing the mask may be removed. The operations to produce the surface finish may or may not significantly change the level of the exposed surface.

[0079] In other embodiments where a third distinct surface finish is desired a further mask of selected configuration may be placed on or contacted to the surface leaving openings in the regions to be treated. The selective treatment may be applied after which the mask may be removed. In still other embodiments surface treatments that are performed may include deposition operations or redistribution operations (e.g. alternate etchings and depositions) as opposed to, or in addition to, the removal operations.

[0080] The method embodiments of the present invention may be implemented manually or via an automated or semi-automated apparatus. The apparatus used for either manual or automated execution of the method will involve appropriate deposition stations (e.g. one or more selective deposition stations, one or more blanket deposition stations, one or more removal stations set up or modifiable to implement the specific type of removal operations to be performed, capability to monitor deposit height or level during removal operations or between removal operations. Various apparatus configurations are within the skill of the art based on the teachings herein. A number of alternatives are disclosed in the previously referenced and incorporated '630 patent.

[0081] Preferred apparatus for implementing the present invention will involve one or more programmed computers that control the process flow and associated operations and parameters. In some embodiments, preferred apparatus will may include, one or more deposition or etching stations for electrodepositing material (e.g. via electroplating), one or more cleaning or activation stations, one or more inspection stations, and one or more layer finishing stations.

[0082] Various other embodiments of the present invention exist. Some of these embodiments may be based on a combination of the teachings herein with various teachings incorporated herein by reference. Some embodiments may not use any blanket deposition process. Some embodiments may involve the selective deposition of a plurality of different materials on a single layer or on different layers. Some embodiments may use blanket depositions processes that are not electrodeposition processes. Some embodiments may use selective deposition processes on some layers that are not conformable contact masking processes and are not even electrodeposition processes. Some embodiments may use nickel as a structural material while other embodiments may use different materials such as gold, silver, or any other electrodepositable materials that can be separated from a sacrificial material such as copper. Some embodiments may use copper as the structural material with or without a sacrificial material. Some embodiments may remove a sacrificial material while other embodiments may not. In some embodiments the anode may be different from the conformable contact mask support and the support may be a porous structure or other perforated structure. Some embodiments may use multiple conformable contact masks with different patterns so as to deposit different selective patterns of material on different layers and/or on different portions of a single layer. In some embodiments, the depth of deposition will be enhanced by pulling the conformable contact mask away from the substrate as deposition is occurring in a manner that allows the seal between the conformable portion of the CC mask and the substrate to shift from the face of the conformal material to the inside edges of the conformable material. In some embodiments, manual or automated visual inspection of a deposits or planarized surfaces may occur. 1 US Application No. Title Filing Date Brief Description US App. No. 09/488,142 Method for Electrochemical Fabrication Jan. 20, 2000 This application is a divisional of the application that led to the above noted ‘630 patent. This application describes the basics of conformable contact mask plating and electrochemical fabrication including various alternative methods and apparatus for practicing EFAB as well as various methods and apparatus for constructing conformable contact masks US App. No. 09/755,985 Microcombustor and Combustion-Based Thermoelectric Microgenerator Jan. 5, 2001 Describes a generally toroidal counterflow heat exchanger and electric current microgenerator that can be formed using electrochemical fabrication. US App. No. 60/329,654 “Innovative Low-Cost Manufacturing Technology for High Aspect Ratio Oct. 15, 2001 Microelectromechanical Systems (MEMS)” A conformable contact masking technique where the depth of deposition is enhanced by pulling the mask away from the substrate as deposition is occurring in such away that the seal between the conformable portion of the mask and the substrate shifts from the face of the conformal material and the opposing face of the substrate to the inside edges of the conformable material and the deposited material. US App. No. 60/364,261 Electrochemical Fabrication Method and Apparatus for Producing Three-Dimensional Mar. 13, 2002 Structures Having Improved Surface Finish An electrochemical fabrication (EFAB) process and apparatus are provided that remove material deposited on at least one layer using a first removal process that includes one or more operations having one or more parameters, and remove material deposited on at least one different layer using a second removal process that includes one or more operations having one or more parameters, wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter. US App. No. 60/379,136 Selective Electrochemical Deposition Methods Having Enhanced Uniform Deposition May 7, 2002 Capabilities Describes conformable contact mask processes for forming selective depositions of copper using a copper pyrophosphate plating solution that allows simultaneous deposition to at least one large area (greater than about 1.44 mm2) and at least one small area (smaller than about 0.05 mm2) wherein the thickness of deposition to the smaller area is no less than one-half the deposition thickness to the large area when the deposition to the large area is no less than about 10 &mgr;m in thickness and where the copper pyrophosphate solution contains at least 30 g/L of copper. The conformable contact mask process is particularly focused on an electrochemical fabrication process for producing three-dimensional structures from a plurality of adhered layers. US App. No. 60/379,131 Selective Electrode position Using Conformable Contact Masks Having Enhanced May 7, 2002 Longevity Describes conformable contact masks that include a support structure and a patterned elastomeric material and treating the support structure with a corrosion inhibitor prior to combining the support and the patterned elastomeric material to improve the useful life of the mask. Also describes operating the plating bath at a low temperature so as to extend the life of the mask. US App. No. 60/379,132 Methods and Apparatus for Monitoring Deposition Quality During Conformable Contact May 7, 2002 Mask Plating Operations Describes an electrochemical fabrication process and apparatus that includes monitoring of at least one electrical parameter (e.g. voltage) during selective deposition using conformable contact masks where the monitored parameter is used to help determine the quality of the deposition that was made. If the monitored parameter indicates that a problem occurred with the deposition, various remedial operations are undertaken to allow successful formation of the structure to be completed. US App. No. 60/379,129 Conformable Contact Masking Methods and Apparatus Utilizing In Situ Cathodic May 7, 2002 Activation of a Substrate An electrochemical fabrication process benefiting from an in situ cathodic activation of nickel is provided where prior to nickel deposition, the substrate is exposed to the desired nickel plating solution and a current less than that capable of causing deposition is applied through the plating solution to the substrate (i.e. cathode) to cause activation of the substrate, after which, without removing the substrate from the plating bath, the current is increased to a level which causes deposition to occur. US App. No. 60/379,134 Electrochemical Fabrication Methods With Enhanced Post Deposition Processing May 7, 2002 An electrochemical fabrication process for producing three-dimensional structures from a plurality of adhered layers is provided where each layer includes at least one structural material (e.g. nickel) and at least one sacrificial material (i.e. copper) that will be etched away from the structural material after the formation of all layers have been completed. A copper etchant containing chlorite (e.g. Enthone C-38) is combined with a corrosion inhibitor (e.g. sodium nitrate) to prevent pitting of the structural material during removal of the sacrificial material. US App. No. 60/379,130 Methods and Apparatus for Electrochemically Fabricating Structures Via Selective May 7, 2002 Etching and Filling of Voids Multilayer structures are electrochemically fabricated using a deposition of a first material, a selective etching of the first deposited material, e.g. via conformable contact masking, and then a deposition of a second material to fill in the voids created by the etching of the first material and then followed by a planarization operation. The first and second depositions may be blanket depositions or selective depositions (e.g. via conformable contact masking). The repetition of the formation process for forming successive layers may be repeated without variation or with variation (e.g. varying patterns; varying the number of depositions, etchings, and or planarization operations; varying the order of operations, varying the materials deposited, even eliminating the selective etching operations on some layers. US App. No. 60/379,133 Method of and Apparatus for Forming Three-Dimensional Structures Integral With May 7, 2002 Semiconductor Based Circuitry An electrochemical fabrication (e.g. by EFAB ™) process and apparatus are provided that can form three-dimensional multi-layer structures using semiconductor based circuitry as a substrate. Electrically functional portions of the structure are formed from structural material (e.g. nickel) that adheres to contact pads of the circuit. Aluminum contact pads and silicon structures are protected from copper diffusion damage by application of appropriate barrier layers. In some embodiments, nickel is applied to the aluminum contact pad via solder bump formation techniques using electroless nickel plating. US App. No. 60/379,176 Selective Electrochemical Deposition Methods Using Pyrophosphate Copper Plating May 7, 2002 Baths Containing Citrate Salts An electrochemical fabrication (e.g. by EFAB ™) process and apparatus are provided that can form three -dimensional multi-layer structures using pyrophosphate copper plating solutions that contain a citrate salt. In preferred embodiments the citrate salts are provided in concentrations that yield improved anode dissolution, reduced formation of pinholes on the surface of deposits, reduced likelihood of shorting between anode and cathode during deposition processes, and reduced plating voltage throughout the period of deposition. A preferred citrate salt is ammonium citrate in concentrations ranging from somewhat more that about 10 g/L for 10 mA/cm2 current density to as high as 200 g/L or more for a current density as high as 40 mA/cm2. US App. No. 60/379,135 Methods of and Apparatus for Molding Structures Using Sacrificial Metal Patterns May 7, 2002 Molded structures, methods of and apparatus for producing the molded structures are provided. At least a portion of the surface features for the molds are formed from multilayer electrochemically fabricated structures (e.g. fabricated by the EFAB ™ formation process), and typically contain features having resolutions within the 1 to 100 &mgr;m range. The layered structure is combined with other mold components, as necessary, and a molding material is injected into the mold and hardened. The layered structure is removed (e.g. by etching) along with any other mold components to yield the molded article. In some embodiments portions of the layered structure remain in the molded article and in other embodiments an additional molding material is added after a partial or complete removal of the layered structure. US App. No. 60/379,177 Electrochemically Fabricated Structures Having Dielectric Bases and Methods of and May 7, 2002 Apparatus for Producing Such Structures Multilayer structures are electrochemically fabricated (e.g. by EFAB ™) on a temporary conductive substrate and are there after are bonded to a permanent dielectric substrate and removed from the temporary substrate. The structures are formed from top layer to bottom layer, such that the bottom layer of the structure becomes adhered to the permanent substrate. The permanent substrate may be a solid sheet that is bonded (e.g. by an adhesive) to the layered structure or the permanent substrate may be a flowable material that is solidified adjacent to or partially surrounding a portion of the structure with bonding occurs during solidification. The multilayer structure may be released from a sacrificial material prior to attaching the permanent substrate or more preferably it may be released after attachment. US App. No. 60/379,182 Electrochemically Fabricated Hermetically Sealed Microstructures and Methods of and May 7, 2002 Apparatus for Producing Such Structures Multilayer structures are electrochemically fabricated (e.g. by EFAB ™) from at least one structural material (e.g. nickel), at least one sacrificial material (e.g. copper), and at least one sealing material (e.g. solder). The layered structure is made to have a desired configuration which is at least partially and immediately surrounded by sacrificial material which is in turn surrounded almost entirely by structural material. The surrounding structural material includes openings in the surface through which etchant can attack and remove trapped sacrificial material found within. Sealing material is located near the openings. After removal of the sacrificial material, the box is evacuated or filled with a desired gas or liquid. Thereafter, the sealing material is made to flow, seal the openings, and resolidify. US App. No. 60/379,184 Multistep Release Method for Electrochemically Fabricated Structures May 7, 2002 Multilayer structures are electrochemically fabricated (e.g. by EFAB ™) from at least one structural material (e.g. nickel), that is configured to define a desired structure and which may be attached to a support structure, and at least a first sacrificial material (e.g. copper) that surrounds the desired structure, and at least one more material which surrounds the first sacrificial material and which will function as a second sacrificial material. The second sacrificial material is removed by an etchant and/or process that does not attack the first sacrificial material. Intermediate post processing activities may occur, and then the first sacrificial material is removed by an etchant or process that does not attack the at least one structural material to complete the release of the desired structure. US App. No. 60/392,531 Miniature RF and Microwave Components and Methods for Fabricating Such June 27, 2002 Components RF and microwave radiation directing or controlling components are provided that are monolithic, that are formed from a plurality of electrodeposition operations, that are formed from a plurality of deposited layers of material, that include inductive and capacitive stubs or spokes that short a central conductor of a coaxial component to the an outer conductor of the component, that include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials and that are useful, and/or that include surface ripples on the inside surfaces of some radiation flow passages. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and/or back filling operations). US App. No. 60/415,374 Monolithic Structures Including Alignment and/or Retention Fixtures Oct. 1. 2002 for Accepting Components Permanent or temporary alignment and/or retention structures for receiving multiple components are provided. The structures are preferably formed monolithically via a plurality of deposition operations (e.g. electrodeposition operations). The structures typically include two or more positioning fixtures that control or aid in the positioning of components relative to one another, such features may include (1) positioning guides or stops that fix or at least partially limit the positioning of components in one or more orientations or directions, (2) retention elements that hold positioned components in desired orientations or locations, and (3) positioning and/or retention elements that receive and hold adjustment modules into which components can be fixed and which in turn can be used for fine adjustments of position and/or orientation of the components. US App. No. 10/271,574 Methods of and Apparatus for Making High Aspect Ratio Microelectromechanical Oct. 15, 2002 Structures Various embodiments of the invention present techniques for forming structures (e.g. HARMS-type structures) via an electrochemical extrusion (ELEX ™) process. Preferred embodiments perform the extrusion processes via depositions through anodeless conformable contact masks that are initially pressed against substrates that are then progressively pulled away or separated as the depositions thicken. A pattern of deposition may vary over the course of deposition by including more complex relative motion between the mask and the substrate elements. Such complex motion may include rotational components or translational motions having components that are not parallel to an axis of separation. More complex structures may be formed by combining the ELEX ™ process with the selective deposition, blanket deposition, planarization, etching, and multi-layer operations of EFAB ™ US App. No. 60/422,008 EFAB Methods and Apparatus Including Spray Metal Coating Processes Oct. 29, 2002 Various embodiments of the invention present techniques for forming structures via a combined electrochemical fabrication process and a thermal spraying process. In a first set of embodiments, selective deposition occurs via conformable contact masking processes and thermal spraying is used in blanket deposition processes to fill in voids left by selective deposition processes. In a second set of embodiments, selective deposition via a conformable contact masking is used to lay down a first material in a pattern that is similar to a net pattern that is to be occupied by a sprayed metal. In these other embodiments a second material is blanket deposited to fill in the voids left in the first pattern, the two depositions are planarized to a common level that may be somewhat greater than a desired layer thickness, the first material is removed (e.g. by etching), and a third material is sprayed into the voids left by the etching operation. The resulting depositions in both the first and second sets of embodiments are planarized to a desired layer thickness in preparation for adding additional layers to form three-dimensional structures from a plurality of adhered layers. In other embodiments, additional materials may be used and different processes may be used. US App. No. 60/422,007 Medical Devices and EFAB Methods and Apparatus for Producing Them Oct. 29, 2002 Various embodiments of the invention present miniature medical devices that may be formed totally or in part using electrochemical fabrication techniques. Sample medical devices include micro-tweezers or forceps, internally expandable stents, bifurcated or side branch stents, drug eluting stents, micro-valves and pumps, rotary ablation devices, electrical ablation devices (e.g. RF devices), micro-staplers, ultrasound catheters, and fluid filters. In some embodiments devices may be made out of a metal material while in other embodiments they may be made from a material (e.g. a polymer) that is molded from an electrochemically fabricated mold. Structural materials may include gold, platinum, silver, stainless steel, titanium or pyrolytic carbon-coated materials such as nickel, copper, and the like. US App. No. 60/422,982 Sensors and Actuators and Methods and Apparatus for Producing Them Nov. 1, 2002 Various embodiments of the invention present sensors or actuators that include a plurality of capacitor (i.e. conductive) plates that can interact with one another to change an electrical parameter that may be correlated to a physical parameter such as pressure, movement, temperature, or the like or that may be driven may an electrical signal to cause physical movement. In some embodiments the sensors or actuators are formed at least in part via electrochemical fabrication (e.g. EFAB). US App. No. 60/429,483 Multi-cell Masks and Methods and Apparatus for Using Such Masks To Form Three- Nov. 26, 2002. Dimensional Structures Multilayer structures are electrochemically fabricated via depositions of one or more materials in a plurality of overlaying and adhered layers. Selectivity of deposition is obtained via a multi-cell controllable mask. Alternatively, net selective deposition is obtained via a blanket deposition and a selective removal of material via a multi-cell mask. Individual cells of the mask may contain electrodes comprising depositable material or electrodes capable of receiving etched material from a substrate. Alternatively, individual cells may include passages that allow or inhibit ion flow between a substrate and an external electrode and that include electrodes or other control elements that can be used to selectively allow or inhibit ion flow and thus inhibit significant deposition or etching. US App. No. 60/429,484 Non-Conformable Masks and Methods and Apparatus for Forming Three-Dimensional Nov. 26, 2002. Structures Electrochemical Fabrication may be used to form multilayer structures (e.g. devices) from a plurality of overlaying and adhered layers. Masks, that are independent of a substrate to be operated on, are generally used to achieve selective patterning. These masks may allow selective deposition of material onto the substrate or they may allow selective etching of a substrate where after the created voids may be filled with a selected material that may be planarized to yield in effect a selective deposition of the selected material. The mask may be used in a contact mode or in a proximity mode. In the contact mode the mask and substrate physically mate to form substantially independent process pockets. In the proximity mode, the mask and substrate are positioned sufficiently close to allow formation of reasonably independent process pockets. In some embodiments, masks may have conformable contact surfaces (i.e. surfaces with sufficient deformability that they can substantially conform to surface of the substrate to form a seal with it) or they may have semi-rigid or even rigid surfaces. Post deposition etching operations may be performed to remove flash deposits (thin undesired deposits). US App. No. 10/309,521 Miniature RF and Microwave Components and Methods for Fabricating Such Dec. 3. 2002. Components RF and microwave radiation directing or controlling components are provided that may be monolithic, that may be formed from a plurality of electrodeposition operations and/or from a plurality of deposited layers of material, that may include switches, inductors, antennae, transmission lines, filters, and/or other active or passive components. Components may include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and/or back filling operations). US App. No. 60/430,809 Electrochemically Fabricated Hermetically Sealed Microstructures and Methods of and Dec. 3, 2002. Apparatus for Producing Such Structures Multilayer structures are electrochemically fabricated (e.g. by EFAB ™) from at least one structural material (e.g. nickel), at least one sacrificial material (e.g. copper), and at least one sealing material (e.g. solder). The layered structure is made to have a desired configuration which is at least partially and immediately surrounded by sacrificial material which is in turn surrounded almost entirely by structural material. The surrounding structural material includes openings in the surface through which etchant can attack and remove trapped sacrificial material found within. Sealing material is located near the openings. After removal of the sacrificial material, the box is evacuated or filled with a desired gas or liquid. Thereafter, the sealing material is made to flow, seal the openings, and resolidify. US App. No. 10/313,795 Complex Microdevices and Apparatus and Methods for Fabricating Such Devices Dec. 6, 2002. Various embodiments of the invention are directed to various microdevices including sensors, actuators, valves, scanning mirrors, accelerometers, switches, and the like. In some embodiments the devices are formed via electrochemical fabrication (EFAB ™). US App No. 60/435,324 EFAB Methods and Apparatus Including Spray Metal or Powder Coating Processes Dec. 20, 2002 Various embodiments of the invention present techniques for forming structures via a combined electrochemical fabrication process and a thermal spraying process or powder deposition processes. In a first set of embodiments, selective deposition occurs via conformable contact masking processes and thermal spraying or powder deposition is used in blanket deposition processes to fill in voids left by selective deposition processes. In a second set of embodiments, selective deposition via a conformable contact masking is used to lay down a first material in a pattern that is similar to a net pattern that is to be occupied by a sprayed metal. In these other embodiments a second material is blanket deposited to fill in the voids left in the first pattern, the two depositions are planarized to a common level that may be somewhat greater than a desired layer thickness, the first material is removed (e.g. by etching), and a third material is sprayed into the voids left by the etching operation. The resulting depositions in both the first and second sets of embodiments are planarized to a desired layer thickness in preparation for adding additional layers to form three-dimensional structures from a plurality of adhered layers. In other embodiments, additional materials and selective depositions other than conformable contact masking processes may be used. US App. No. 60/442, 166 Silicone Compositions, Methods of Making, and Uses Thereof Jan. 22, 2003 Silicone based compositions having enhanced UV absorption are provided. US App. No. 60/442,656 Electrochemically Fabricated Structures Having Dielectric or Active Bases and Methods Jan. 23, 2003. of and Apparatus for Producing Such Structures Multilayer structures are electrochemically fabricated (e.g. by EFAB ™) on a temporary conductive substrate and are there after are bonded to a permanent dielectric substrate and removed from the temporary substrate. The structures are formed from top layer to bottom layer, such that the bottom layer of the structure becomes adhered to the permanent substrate. The permanent substrate may be a solid sheet that is bonded (e.g. by an adhesive) to the layered structure or the permanent substrate may be a flowable material that is solidified adjacent to or partially surrounding a portion of the structure with bonding occurs during solidification. The multilayer structure may be released from a sacrificial material prior to attaching the permanent substrate or more preferably it may be released after attachment.

[0083] Various other embodiments of the present invention exist. Some of these embodiments may be based on a combination of the teachings herein with various teachings incorporated herein by reference. Some embodiments may not use any blanket deposition process. Some embodiments may involve the selective deposition of a plurality of different materials on a single layer or on different layers. Some embodiments may use blanket depositions processes that are not electrodeposition processes. Some embodiments may use selective deposition processes that are not conformable contact masking processes (on some or on all layers) and are not even electrodeposition processes. Some embodiments may replace selective deposition processes with a combination of one or more selective etching operations and one or more blanket deposition operations. Some embodiments may use nickel as a structural material while other embodiments may use different materials such as gold, silver, or any other electrodepositable materials (or even non-electrodepositable material) that can be separated from a selected (e.g. copper) sacrificial material or materials. Some embodiments may use copper as the structural material with or without a sacrificial material. Some embodiments may remove a sacrificial material while other embodiments may not. In some embodiments an anode may be different from the conformable contact mask support and the support may be a porous structure or other perforated structure. Some embodiments may use multiple conformable contact masks with different patterns so as to deposit different selective patterns of material on different layers and/or on different portions of a single layer. In some embodiments, non-conformable contact masks may be used or masks that are formed on and temporarily adhered to the substrate may be used. In some embodiments, the depth of deposition will be enhanced by pulling the conformable contact mask away from the substrate as deposition is occurring in a manner that allows the seal between the conformable portion of the CC mask and the substrate to shift from the face of the conformal material to the inside edges of the conformable material.

[0084] In view of the teachings herein, many further embodiments, alternatives in design and uses of the instant invention will be apparent to those of skill in the art. As such, it is not intended that the invention be limited to the particular illustrative embodiments, alternatives, and uses described above but instead that it be solely limited by the claims presented hereafter.

Claims

1. An electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) supplying a plurality of preformed masks, wherein each mask comprises a patterned conformable dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned conformable dielectric material;

(B) selectively depositing at least a portion of a layer onto the substrate, wherein the substrate may comprise previously deposited material;

(C) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming comprises repeating operation (B) a plurality of times;

wherein at least a plurality of the selective depositing operations comprise

(1) contacting the substrate and the conformable material of a selected preformed mask;

(2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, wherein the anode comprises a selected deposition material, and wherein the substrate functions as a cathode, such that the selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) separating the selected preformed mask from the substrate; and

(D) removing material deposited on at least one layer using a first removal process that comprises one or more operations having one or more parameters; and

(E) removing material deposited on at least one different layer using a second removal process that comprises one or more operations having one or more parameters,

wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter.

2. The process of claim 1 wherein the first and second removal processes comprise lapping operations, and wherein one of the removal processes comprises a lapping operation that uses a finer abrasive than that used by the other removal process.

3. The process of claim 1 wherein the first and second removal processes comprise lapping operations, and wherein one of the removal processes comprises one or more additional lapping operations than does the other removal process.

4. The process of claim 1 wherein one of the first or second removal processes comprises a finer removal process than the other removal process.

5. The process of claim 4 wherein the finer removal process results in a surface with mirror-like optical properties.

6. The process of claim 4 wherein the finer removal process is used after deposition of material for a final layer of the structure.

7. The process of claim 4 wherein the finer removal process is used after deposition of material for an intermediate layer of the structure.

8. The process of claim 5 wherein the mirror-like properties exist on a surface of the structure that undergoes a removal process.

9. The process of claim 5 wherein the mirror-like properties exist on a surface of the structure that did not undergo a removal process but instead acquired the mirror-like properties as a result of deposition of material onto a mirror-like surface.

10. The process of claim 1 wherein the formation of a plurality of layers includes the deposition of at least a second material.

11. The process of claim 10 wherein the second material is a structural material and the selected deposition material is a sacrificial material

12. The process of claim 1 wherein at least one of the first and second removal processes comprises CMP.

13. The process of claim 1 wherein at least one of the first or second removal processes comprise multiple lapping operations where at least two different abrasives are used.

14. The process of claim 13 wherein use of a rougher abrasive on a given layer is followed by use of a finer abrasive.

15. The process of claim 13 wherein use of a finer abrasive is followed by use of a rougher abrasive

16. The process of claim 15 wherein finer abrasive is used for a longer time than the rougher abrasive.

17. The process of claim 1 wherein depositions associated with at least one or more layers are subjected to a third removal process that is different from both the first and second removal processes.

18. The process of claim 1 wherein the conformable material comprises an elastomeric material.

19. The process of claim 11 wherein at least one of the removal processes involves use of a selective etchant that attacks either the sacrificial material or the structural material but not both.

20. The process of claim 1 wherein at least one of the removal processes involves use of an electropolishing process.

21. An electrochemical fabrication apparatus for producing a three-dimensional structure from a plurality of adhered layers, the apparatus comprising:

(A) a plurality of preformed masks, wherein each mask comprises a patterned conformable dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned conformable dielectric material;

(B) means for selectively depositing at least a portion of a layer onto the substrate, wherein the substrate may comprise previously deposited material; and

(C) means for forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming comprises repeating operation (B)a plurality of times;

wherein the means for selectively depositing comprises

(1) means for contacting the substrate and the conformable material of a selected preformed mask;

(2) means for conducting, in presence of a plating solution, an electric current through the at least one opening in the selected mask between an anode and the substrate, wherein the anode comprises a selected deposition material, and wherein the substrate functions as a cathode, such that the selected deposition material is deposited onto the substrate to form at least a portion of a layer; and

(3) means for separating the selected preformed mask from the substrate; and

(D) means for removing material deposited on at least one layer using a first removal process that comprises one or more operations having one or more parameters; and

(E) means for removing material deposited on at least one different layer using a second removal process that comprises one or more operations having one or more parameters,

wherein the first removal process differs from the second removal process by inclusion of at least one different operation or at least one different parameter.

22. An electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) forming at least a portion of a layer by either selectively depositing a material, to form portion of a layer, onto a substrate or by selectively etching into a previously deposited material that occupies at least a portion of a layer and then depositing a material into an opening formed by the selective etching, wherein the substrate may comprise previously deposited layers of material;

(B) forming a plurality of layers such that subsequent layers are formed adjacent to and adhered to previously deposited layers;

(C) finishing a surface of at least a portion of one or more materials deposited on at least one layer using a first process that comprises one or more operations having one or more parameters; and

(E) finishing a surface of at least a portion of one or more materials deposited on at least one different layer using a second process that comprises one or more operations having one or more parameters,

wherein the first process differs from the second process by inclusion of at least one different operation, removal of at least one operation, or use of at least one different parameter value.

23. The process of claim 22 wherein a determination of a finishing operation or parameter for finishing at least one layer or of the at least one different layer is at least in part determined from a relationship between portions of one layer and portions of an adjacent layer.

24. The process of claim 22 wherein a mask is used to define at least one opening which exposes a surface that is to undergo a selected finishing operation and where unexposed portions of the surface define a portion of the surface that is not to undergo the selected finishing operation.

25. The process of claim 23 wherein the relationship involves a determination of whether portions of a structural material are outward facing.

26. The process of claim 25 wherein the outward facing portion is up-facing and a build orientation comprises forming subsequent layers above previously formed layers.

27. The process of claim 25 wherein the outward facing portion is down-facing and a build orientation comprises forming subsequent layers above previously formed layers.

28. The process of claim 25 wherein the outward facing portion is up-facing and a build orientation comprises forming subsequent layers below previously formed layers.

29. The process of claim 25 wherein the outward facing portion is down-facing and a build orientation comprises forming subsequent layers below previously formed layers.

30. An electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process comprising:

(A) forming at least a portion of a layer by either selectively depositing a material, to form portion of a layer, onto a substrate or by selectively etching into a previously deposited material that occupies at least a portion of a layer and then depositing a material into an opening formed by the selective etching, wherein the substrate may comprise previously deposited layers of material;

(B) forming a plurality of layers such that subsequent layers are formed adjacent to and adhered to previously deposited layers;

(C) finishing a surface of at least a portion of one or more materials deposited on at least one layer using a first process that comprises one or more operations having one or more parameters; and

(E) finishing a surface of at least a portion of one or more materials deposited on the at least one layer using a second process that comprises one or more operations having one or more parameters,

wherein the portions subject to the first and second processes are not identical and wherein the first process differs from the second process by inclusion of at least one different operation, removal of at least one operation, or use of at least one different parameter value.

31. The process of claim 30 wherein the first process acts upon a portion of the at least one layer and the second process acts upon a portion of the at least one layer that includes a region not acted upon by the first process.

32. The process of claim 30 wherein the first process acts upon a portion of the at least one layer and the second process acts upon a portion of the at least one layer that is exclusive of the portion acted upon by the first process.

33. The process of claim 30 a determination of which portion of the at least one layer is to be undergo finishing using the first process or using the second process is at least in part determined from a relationship between portions of the at least one layer and portions of an adjacent layer.

34. The process of claim 30 wherein a mask is used to define at least one opening which exposes a surface that is to undergo a selected finishing operation and where unexposed portions of the surface define a portion of the surface that is not to undergo the selected finishing operation.

35. The process of claim 31 wherein the relationship involves a determination of whether portions of a structural material are outward facing.

36. The process of claim 35 wherein the outward facing portion is up-facing and a build orientation comprises forming subsequent layers above previously formed layers.

37. The process of claim 35 wherein the outward facing portion is down-facing and a build orientation comprises forming subsequent layers above previously formed layers.

38. The process of claim 35 wherein the outward facing portion is up-facing and a build orientation comprises forming subsequent layers below previously formed layers.

39. The process of claim 35 wherein the outward facing portion is down-facing and a build orientation comprises forming subsequent layers below previously formed layers.

40. The process of claim 35 wherein the relationship involves a determination of whether portions of a structural material continue from one layer to a subsequent layer.

41. The process of claim 35 wherein the relationship involves a determination of whether portions of a sacrificial material continue from one layer to a subsequent layer.