Apparatus for Cleaning a Semiconductor Substrate
An apparatus for processing a substrate is provided. The apparatus includes a solid material having a support side and a contact side. The contact side has an outer surface, and the outer surface is configured to become softer relative to a remainder of the solid material when exposed to an activation solution. The apparatus includes a support structure configured to support the solid material from the support side of the solid material, such that the contact side of the solid material is oriented to face a surface of the substrate, when the substrate is present. Also provided is a gimbaled structure connected to the support structure. The gimbaled structure enabling the outer surface of the contact side to substantially align in a coplanar arrangement with the surface of the substrate, when the substrate is present. A force application structure is coupled to the gimbaled structure. The force application structure is configured for moving the solid material toward and away from the surface of the substrate, when the substrate is present, and further configured for applying a force that presses the outer surface of the solid material against the surface of the substrate, when the substrate is present.
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This application is a divisional of U.S. patent application Ser. No. 13/661,929, filed on Oct. 26, 2012, entitled “Methods for Cleaning a Semiconductor Substrate,” which is a divisional application of U.S. patent application Ser. No. 11/612,352, filed on Dec. 18, 2006 (since issued as U.S. Pat. No. 8,316,866), entitled “Method and Apparatus for Cleaning A Semiconductor Substrate.” Each above-identified application is hereby incorporated by reference.
CROSS REFERENCE To RELATED APPLICATIONSThis application claims the benefit of U.S. Provisional Application No. 60/755,377, filed Dec. 30, 2005. Additionally, this application is a continuation-in-part of prior application Ser. No. 10/608,871, filed Jun. 27, 2003, and entitled “Method and Apparatus for Removing a Target Layer From a Substrate Using Reactive Gases.” The disclosure of each of the above-identified applications is incorporated herein by reference for all purposes. This application is related to U.S. patent application Ser. No. 10/816,337, filed on Mar. 31, 2004, and entitled “Apparatuses and Methods for Cleaning a Substrate,” and U.S. patent application Ser. No. 11/173,132, filed on Jun. 30, 2005, and entitled “System and Method for Producing Bubble Free Liquids for Nanometer Scale Semiconductor Processing,” and U.S. patent application Ser. No. 11/153,957, filed on Jun. 15, 2005, and entitled “Method and Apparatus for Cleaning a Substrate Using Non-Newtonian Fluids,” and U.S. patent application Ser. No. 11/154,129, filed on Jun. 15, 2005, and entitled “Method and Apparatus for Transporting a Substrate Using Non-Newtonian Fluid,” and U.S. patent application Ser. No. 11/174,080, filed on Jun. 30, 2005, and entitled “Method for Removing Material from Semiconductor Wafer and Apparatus for Performing the Same,” and U.S. patent application Ser. No. 10/746,114, filed on Dec. 23, 2003, and entitled “Method and Apparatus for Cleaning Semiconductor Wafers using Compressed and/or Pressurized Foams, Bubbles, and/or Liquids,” and U.S. patent application Ser. No. 11/336,215 filed on Jan. 20, 2006, and entitled “Method and Apparatus for Removing Contamination from Substrate,” U.S. patent application Ser. No. 11/346,894 filed on Feb. 3, 2006 and entitled “Method for Removing Contamination from a Substrate and for Making a Cleaning Solution,” U.S. patent application Ser. No. 11/347,154 filed on Feb. 3, 2006 and entitled “Cleaning Compound and Method and System for Using the Cleaning Compound,” U.S. patent application Ser. No. 11/532,491 filed on Sep. 15, 2006 and entitled “Method and material for cleaning a substrate,” U.S. patent application Ser. No. 11/532,493 filed on Sep. 15, 2006 and entitled “Apparatus and system for cleaning a substrate.” The disclosure of each of these related applications is incorporated herein by reference for all purposes.
BACKGROUNDIn the fabrication of semiconductor devices, such as integrated circuits, memory cells, and the like, a series of manufacturing operations are performed to define features on semiconductor wafers. The wafers include integrated circuit devices in the form of multi-level structures defined on a silicon substrate. At a substrate level, transistor devices with diffusion regions are formed. In subsequent levels, interconnected metallization lines are patterned and electrically connected to the transistor devices to define a desired integrated circuit device. Also, patterned conductive layers are insulated from other conductive layers by dielectric materials.
During the series of manufacturing operations, the wafer surface is exposed to various types of contaminants. Essentially, any material present in a manufacturing operation is a potential source of contamination. For example, sources of contamination may include process gases, chemicals, deposition materials, and liquids, among others. The various contaminants may deposit on the surface of a wafer as particulate matter. If the particulate contamination is not removed, the devices within the vicinity of the contamination will likely be inoperable. Thus, it is necessary to clean contamination from the wafer surface in a substantially complete manner without damaging the features defined on the wafer. The size of particulate contamination is often on the order of critical dimension size of the features being fabricated on the wafer. Removal of such small particulate contamination without adversely affecting the features on the wafer can be a challenge.
Conventional wafer cleaning methods have relied heavily on mechanical force to remove particulate contamination from the wafer. As feature size continues to decrease and become more fragile, the probability of feature damage due to application of mechanical force to the wafer surface increases. For example, features having high aspect ratios are vulnerable to toppling or breaking when impacted by a sufficient mechanical force. To further complicate the cleaning problem, the move toward reduced feature sizes also causes a reduction in the size of particulate contamination that may cause damage. Particulate contamination of sufficiently small size can find its way into difficult-to-reach areas on the wafer surface, such as in a trench surrounded by high-aspect ratio features or bridging of conductive lines, etc. Thus, efficient and non-damaging removal of contaminants during marred and semiconductor fabrication represents continuous challenge to be met by continuing advances in wafer cleaning technology. It should be appreciated that the manufacturing operations for flat panel displays suffer from the same shortcomings of the integrated circuit manufacturing discussed above. Thus, any technology requiring contaminant removal is in need of a more effective and less-abrasive cleaning technique.
SUMMARYBroadly speaking, the present invention fills these needs by providing an improved cleaning technique and cleaning solution. It should be appreciated that the present invention can be implemented in numerous ways, including as a system, an apparatus and a method. Several inventive embodiments of the present invention are described below.
In one embodiment, an apparatus for processing a substrate is provided. The apparatus includes a solid material having a support side and a contact side. The contact side has an outer surface, and the outer surface is configured to become softer relative to a remainder of the solid material when exposed to an activation solution. The apparatus includes a support structure configured to support the solid material from the support side of the solid material, such that the contact side of the solid material is oriented to face a surface of the substrate, when the substrate is present. Also provided is a gimbaled structure connected to the support structure. The gimbaled structure enabling the outer surface of the contact side to substantially align in a coplanar arrangement with the surface of the substrate, when the substrate is present. A force application structure is coupled to the gimbaled structure. The force application structure is configured for moving the solid material toward and away from the surface of the substrate, when the substrate is present, and further configured for applying a force that presses the outer surface of the solid material against the surface of the substrate, when the substrate is present.
In one embodiment, a method for cleaning a substrate is provided. The method initiates with applying an activation solution to a surface of the substrate. The activation solution and the surface of the substrate are contacted with a surface of a solid cleaning surface. The activation solution is absorbed into a portion of the solid cleaning element and then the substrate or the solid cleaning surface is moved relative to each other to clean the surface of the substrate.
In another embodiment, a cleaning apparatus for cleaning a substrate is provided. The cleaning apparatus includes a solid material having an outer surface, the outer surface configured to become softer relative to a remainder of the solid material when exposed to an activation solution disposed over a surface of the substrate. The cleaning apparatus includes a support structure configured to support the solid material and apply a force causing the outer surface to contact the surface of the substrate.
In yet another embodiment, a cleaning system for cleaning a substrate is provided. The cleaning system includes a support configured to support the substrate and a fluid delivery system configured to deliver an activation solution to a surface of the substrate. The cleaning system includes a solid phase cleaning element having an exposed surface, the exposed surface has a component that softens relative to a remaining portion of the solid phase cleaning element when the exposed surface interfaces with the activation solution. The cleaning system includes a support structure supporting the solid phase cleaning element. The support structure is configured to maintain the exposed surface against a surface of the substrate during a cleaning operation.
In still yet another embodiment a method for cleaning a substrate is provided. The method includes contacting a substrate surface with a surface of a solid cleaning element and forcing the solid cleaning element against the substrate surface. The method also includes moving one of the solid cleaning element or the substrate relative to each other, where the moving causes a plastic deformation of the surface of the solid cleaning element thereby depositing a layer of the solid cleaning element onto the substrate surface. The method further includes rinsing the layer of the solid cleaning element off of the substrate surface.
In another embodiment, a cleaning apparatus for cleaning a substrate is provided. The cleaning apparatus includes a solid material having an outer surface. The outer surface is configured to deform plastically to prevent damage to the substrate in response to a normal and/or a tangential force being applied to the solid material while one of the substrate or the solid material moves relative to each other. The cleaning apparatus includes a support structure configured to support the solid material and transfer the downward force.
Other aspects and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the present invention.
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, and like reference numerals designate like structural elements.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.
The embodiments described herein provide for a cleaning technique that reduces the abrasive contact and is efficient at cleaning contaminants from a semiconductor substrate which may contain high aspect ratio features. It should be appreciated that while the embodiments provide specific examples related to semiconductor cleaning applications, these cleaning applications may be extended to any technology requiring the removal of contaminants from a surface. The embodiments described herein move a single phase cleaning agent relative to a surface to be cleaned, where materials contained within the solid portion of the single phase cleaning agent provide lifting and removal of particles present on a wafer surface. In one exemplary embodiment, a solid cleaning element is used as the single phase cleaning agent where the cleaning element has a substantially planar surface that is brought in contact with a surface of the substrate to be cleaned. While specific embodiments refer to the element as a solid cleaning element, the solid cleaning element may be referred to as a puck, bar, etc. In one embodiment, the solid cleaning element is composed of a fatty acid, however, other materials may be used just as effectively. These other materials may include polymers, alkyl sulfonate, alkyl phosphate, alkyl phosphonate, biopolymers, proteins, etc.
Thus, some material from the solid cleaning element 100 is rubbed off and deposited on substrate 102 as a coating layer 103 shown in
In the embodiment where the element is a fatty acid, the following are exemplary compounds that may be used to compose the element. It should be appreciated that aliphatic acids represent essentially any acid defined by organic compounds in which carbon atoms form open chains. A fatty acid is an example of an aliphatic acid that can be used as the solid cleaning material as discussed above. Examples of fatty acids that may be used as the solid cleaning element include lauric, palmitic, stearic, oleic, linoleic, linolenic, arachidonic, gadoleic, eurcic, butyric, caproic, caprylic, myristic, margaric, behenic, lignoseric, myristoleic, palmitoleic, nervanic, parinaric, timnodonic, brassic, clupanodonic acid, lignoceric acid, cerotic acid, and mixtures thereof, among others. In one embodiment, the solid cleaning element can represent a mixture of fatty acids defined by various carbon chain lengths extending from C-1 to about C-26. Carboxylic acids are defined by essentially any organic acid that includes one or more carboxyl groups (COOH). When used as the solid cleaning element, the carboxylic acids can include mixtures of various carbon chain lengths extending from C-1 through about C-100. Also, the carboxylic acids can include other functional groups such as but not limited to methyl, vinyl, alkyne, amide, primary amine, secondary amine, tertiary amine, azo, nitrile, nitro, nitroso, pyridyl, peroxy, aldehyde, ketone, primary imine, secondary imine, ether, ester, halogen, isocyanate, isothiocyanate, phenyl, benzyl, phosphodiester, sulfhydryl.
The method of
Although the present invention has been described in the context of removing contaminants from a semiconductor wafer, it should be understood that the previously described principles and techniques of the present invention can be equally applied to cleaning surfaces other than semiconductor wafers. For example, the present invention can be used to clean any equipment surface used in semiconductor manufacturing, wherein any equipment surface refers to any surface that is in environmental communication with the wafer, e.g., shares air space with the wafer. The present invention can also be used in other technology areas where contamination removal is important. For example, the present invention can be used to remove contamination on parts used in the space program, or other high technology areas such as surface science, energy, optics, microelectronics, MEMS, flat-panel processing, solar cells, memory devices, etc. It should be understood that the aforementioned listing of exemplary areas where the present invention may be used is not intended to represent an inclusive listing. Furthermore, it should be appreciated that the wafer as used in the exemplary description herein can be generalized to represent essentially any other structure, such as a substrate, a part, a panel, etc.
While this invention has been described in terms of several embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. Therefore, it is intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention. In the claims, elements and/or steps do not imply any particular order of operation, unless explicitly stated in the claims.
Claims
1. An apparatus for processing a substrate, comprising:
- a solid material having a support side and a contact side, the contact side having an outer surface, the outer surface configured to become softer relative to a remainder of the solid material when exposed to an activation solution;
- a support structure configured to support the solid material from the support side of the solid material, such that the contact side of the solid material is oriented to face a surface of the substrate, when the substrate is present;
- a gimbaled structure connected to the support structure, the gimbaled structure enabling the outer surface of the contact side to substantially align in a coplanar arrangement with the surface of the substrate, when the substrate is present; and
- a force application structure coupled to the gimbaled structure, the force application structure configured for moving of the solid material toward and away from the surface of the substrate, when the substrate is present, and further configured for applying a force that presses the outer surface of the solid material against the surface of the substrate, when the substrate is present.
2. The apparatus of claim 1, wherein the gimbaled structure includes rotation structure to enable movement of the support structure in a least two axis of gimbal.
3. The apparatus of claim 1, wherein the gimbaled structure includes rotation structure to enable movement of the support structure in multiple dimensions.
4. The apparatus of claim 1, wherein the gimbaled structure includes rotation structure includes two or three pairs of pivots mounted on axes at right angles.
5. The apparatus of claim 1, wherein the solid material is selected from a group consisting of a fatty acid, an alkyl sulfonate, an alkyl phosphate, and an alkyl phosphonate.
6. The apparatus of claim 1, wherein the support structure includes a shaft through an axis of the solid material and wherein the solid material rotates around the axis.
7. The apparatus of claim 1, wherein the gimbaled structure is configured for rotation.
8. The apparatus of claim 1, further comprising:
- a fluid delivery system for providing the activation solution to the surface of the substrate, when present.
9. The apparatus of claim 1, wherein the activation solution is alkaline or is a surfactant.
10. The apparatus of claim 1, wherein a component of the outer surface is ionized by the activation solution.
11. The apparatus of claim 1, wherein the outer surface is a planar surface.
12. The apparatus of claim 1, wherein the force causes a plastic deformation of the surface of the solid cleaning element, thereby depositing a layer of the solid cleaning element onto the substrate surface, the layer of the solid cleaning element is configured for rinsing off of the substrate surface.
13. The apparatus of claim 1, wherein the plastic deformation is at least partially caused by a lateral force.
14. An apparatus for processing a substrate, comprising:
- a fatty acid puck having a support side and a contact side, the contact side having an outer surface, the outer surface configured to become softer relative to a remainder of the fatty acid puck when exposed to an activation solution;
- a support structure configured to support the fatty acid puck from the support side of the fatty acid puck, such that the contact side of the fatty acid puck is oriented to face a surface of the substrate, when the substrate is present;
- a gimbaled structure connected to the support structure, the gimbaled structure enabling the outer surface of the contact side to substantially align in a coplanar arrangement with the surface of the substrate, when the substrate is present; and
- a force application structure coupled to the gimbaled structure, the force application structure configured for moving of the fatty acid puck toward and away from the surface of the substrate, when the substrate is present, and further configured for applying a force that presses the outer surface of the fatty acid puck against the surface of the substrate, when the substrate is present.
15. The apparatus of claim 14, wherein the gimbaled structure includes rotation structure to enable movement of the support structure in multiple dimensions.
16. The apparatus of claim 14, wherein the support structure includes a shaft through an axis of the fatty acid puck and wherein the fatty acid puck rotates around the axis.
17. The apparatus of claim 14, wherein the gimbaled structure is configured for rotation, and wherein the force causes a plastic deformation of the surface of the fatty acid puck, thereby depositing a layer of the fatty acid puck onto the substrate surface, the layer of the fatty acid puck is configured for rinsing off of the substrate surface.
18. The apparatus of claim 14, further comprising:
- a fluid delivery system for providing the activation solution to the surface of the substrate, when present, and the activation solution is alkaline or is a surfactant, and a component of the outer surface is ionized by the activation solution.
19. An apparatus for processing a substrate, comprising:
- a bar material having a support side and a contact side, the contact side having an outer surface, the outer surface configured to become softer relative to a remainder of the bar material when exposed to an activation solution;
- a support structure configured to support the bar material from the support side of the bar material, such that the contact side of the bar material is oriented to face a surface of the substrate, when the substrate is present;
- a gimbaled structure connected to the support structure, the gimbaled structure enabling the outer surface of the contact side to substantially align in a coplanar arrangement with the surface of the substrate, when the substrate is present; and
- a force application structure coupled to the gimbaled structure, the force application structure configured for moving of the bar material toward and away from the surface of the substrate, when the substrate is present, and further configured for applying a force that presses the outer surface of the bar material against the surface of the substrate, when the substrate is present.
20. The apparatus of claim 19, wherein the gimbaled structure is configured for rotation, and wherein the force causes a plastic deformation of the surface of the bar material, thereby depositing a layer of the bar material onto the substrate surface, the layer of the bar material is configured for rinsing off of the substrate surface, and further comprising,
- a fluid delivery system for providing the activation solution to the surface of the substrate, when present, and the activation solution is alkaline or is a surfactant, and a component of the outer surface is ionized by the activation solution.
Type: Application
Filed: Oct 16, 2013
Publication Date: Mar 6, 2014
Applicant: Lam Research Corporation (Fremont, CA)
Inventors: Erik M. Freer (Mt.View, CA), John M. deLarios (Palo Alto, CA), Katrina Mikhaylichenko (San Jose, CA), Michael Ravkin (Los Altos, CA), Mikhail Korolik (San Jose, CA), Fred C. Redeker (Fremont, CA)
Application Number: 14/055,850
International Classification: H01L 21/67 (20060101); H01L 21/02 (20060101);