TRACE ANYWHERE INTERCONNECT
The present invention provides for a method and structure for forming three-dimensionally routed dielectric wires between discrete points on the two or more parallel circuit planes. The wires may be freely routed in three-dimensional space as to create the most efficient routing between the two arbitrarily defined points on the two or more parallel circuit planes. Metalizing the outer surfaces of these three dimensional dielectric wires electrically coupling the discrete wires to their respective discrete contact points. Two or more of these wires may be in intimate contact to one another electrically coupling to each other as well as to two or more discrete contact pads. These electrically coupled contact pads may be on opposite sides or on the same side of the structure and the formed metalized wires may originate on one side and terminate on the other or originate and terminate from the same side.
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The present application is a divisional application of U.S. Ser. No. 15/189,435 filed on Jun. 22, 2016 by R&D Circuits, Inc. and claims priority thereunder pursuant to 35 USC 120. A provisional application was filed Ser. No. 62/212,894 on Sep. 1, 2015 by R&D Circuits, Inc.
BACKGROUND 1. FieldThe present application relates to a method and a structure for creating interconnects that are not bound by the limitations of conventional interconnect technology. In particular the present invention relates to forming an electrical interconnect mechanism between two or more discrete contact points such as but not limited to circuit pads within two or more parallel circuit planes with circuitry formed in three-dimensional space between the aforementioned two or more circuit planes in order to allow for electrical coupling of two or more electrical devises through said interconnect device.
2. The Related ArtConventional interconnect technology limits the routing of circuitry to the x-y plane by way of conductive traces. These traces are then connected in the z-axis through holes (vias) formed perpendicular to the traces, aligned over the traces. These vias are then coated or plated with a metallization either partially or completely filled, connecting the traces to circuitry formed in the x-y planes above and below.
It is normal for these interconnect structures to have an array of contact pads on either side of the outer major surfaces of the structure and occasionally even on the minor sides or surfaces of the structure. These contact pads are meant to be electrically coupled with electronic components on the outer surfaces. When there are a large number of contact pads or points on each side to be electrically coupled the internal circuitry layers become very dense and require a large number of routing layers. Each of these layers are traditionally formed in layer pairs of two, sandwiched on both sides of a dielectric sheet. These sheets are manufactures concurrently then bonded together with additional dielectric sheet layers forming multilayered structures. Vias are then formed and metalized through or partially through these layer stacks making the required z axis interconnects. Partial or buried vias can be formed and metalized on each of the layer pairs prior to bonding the layers together.
Alternatively, to improve routing density dielectric layers and circuitry layers can be built up one on top of another sequentially with blind vias formed only where necessary. This eliminates the need of through vias, which take up routing space in the x-y planes on layers where the vias is not essential. This via anywhere approach greatly improved routing density but suffers from the cost of time and labor to build these layers sequentially.
SUMMARYThe present invention provides a method and a structure in which an electrical interconnect mechanism is formed having complex connections between two or more discrete contact points such as but not limited to circuit pads within two or more parallel circuit planes with circuitry formed in three-dimensional space between the aforementioned two or more circuit planes, In this way the present invention provides for electrical coupling of two or more electrical devices through said interconnect device. In particular the present invention provides for a method and structure for forming three-dimensionally routed dielectric wires between discrete points on the two or more parallel circuit planes. These wires may be freely routed in three-dimensional space as to create the most efficient routing between the two arbitrarily defined points on the two or more parallel circuit planes. Metalizing the outer surfaces of these three dimensional dielectric wires electrically coupling the discrete wires to their respective discrete contact points. Two or more of these wires may be in intimate contact to one another electrically coupling to each other as well as to two or more discrete contact pads. These electrically coupled contact pads may be on opposite sides or on the same side of the structure and the formed metalized wires may originate on one side and terminate on the other or originate and terminate from the same side. Optionally, forming a second coating of dielectric on the metalized surfaces of the discrete wires to a specific thickness as to approximate a coaxial wire. These formed and metalized dielectric wire may be electrically coupled through the metallization process to discrete metallic circuits on the two or more planes or the discrete parallel circuits may be formed as an integral part of the formed dielectric wires and then metalized along with the dielectric wires. Other embodiments and variations of the present invention are described below.
Referring now to the drawings of
As shown
The outer surfaces of these three dimensional dielectric wires 6 prior to electrically coupling the discrete wires 6 to their respective discrete contact points 10 should be metalized 3 (see
In the embodiment for the optionally formed second coating of dielectric 6a and metallization 3a of the wires 6 the second metallization 3a on the coated wire 6 is limited to just short of making contact to the discrete circuit elements on either plane 7 (
In another embodiment of the present invention the second metalization coating and or the second dielectric layer on the formed dielectric wires is in intimate contact with one another coupling the outer metallization electrically to each other as well as to one or more points on the outer surface circuit planes. This will have the effect of providing ground shielding and or coaxial wires (See
In lieu of ground shielding formed around the discrete circuit wires 6, alternatively a dielectric wall 15 or plane 15 may be formed in the z-axis or vertically in the structure, transposed between the outer surface circuit planes 7, metalized with the end points electrically coupled to the discrete circuits patterns 8,8a (
Designing the free flow of the three dimensionally formed aforementioned wires to have shapes such as but not limited to coils, cantilevers and S-shapes to provide spring like characteristics to allow for the compliance of the wires while resisting stress cracking in the metal and or dielectric (See
Further, each of the aforementioned embodiments of the present invention can be built with one or more silicon wafer ICs' creating multi chip modules interconnecting the two or more ICs' where a silicon layer is the base circuit plane.
Further, each of the aforementioned embodiments of the present invention can be built with one or more silicon wafer ICs' creating redistribution packaging for the IC.
Further, each of the a forementioned embodiments of the present invention can be built on a flexible circuit base.
The method for the above described embodiment structure is as follows:
In the case of a trace anywhere interconnect with dielectric core wires for the present invention, the starting point is with a flat carrier of glass, ceramic or some other smooth, flat material such as but not limited to s smooth metallic block. Next one should temporarily bond a sheet of metallic foil preferably Cu to the flat material carrier to keep the Cu flat with a suitable bonding material such as but not limited to adhesive or wax. This foil thickness should be in the range but not limited to 10 um to 35 um. Next, on top of the Cu foils, utilizing commercially available 3D printing techniques know in the art, form dielectric wires attached to the Cu foil grow-up from predetermined locations on the foil to predetermined location in free space in the z axis. The foil may be treated to promote adhesion of the dielectric wires through micro-etching plasma or other surface treatment known in the art. These wires will typically be in the range of 1 um to 50 um in diameter. These wires will be built up to a z-axis height approximately 25 um to 100 um above the overall height of the planned interconnect mechanism typically from 100 um to 0.200″ thick.
Next, the free formed wires extending from the Cu sheet are metalized with electro-plating, electro-less plating, Chemical vapor deposition, sputter coating or any other technique known in the art. The thickness of this metallization will typically be in the range of 1 um to 25 um. This metallization will in effect coat the dielectric wires as well as the exposed surface area of the base foil making the base foil and the coated wires electrically coupled.
Optionally, the metalized dielectric wires can be coated again with a dielectric via a dip operation, silicon Chemical Vapor deposition (SCVD) Silica Pulsed layer Deposition (PLD), Titania Atomic Layer Deposition (ALD) or other techniques known in the art. During this process the top side, of the base foil metallization can be coated as well, electrically isolating it from further processes.
The coated wires are then (optionally) metalized via the techniques previously described. This metallization will have the effect of shorting all the surfaces of the formed wires together. Tying this metallization to one or more ground wires or outer circuit layers in effect creates ground shielding for all wires as well as approximates coaxial wires for all signal wires. Coupling this ground metallization can be achieved through selective removal of the outer coating of dielectric, via laser ablation, Milling or some other technique known in the art, from the wires or areas of the base copper designed to be ground when the interconnect ultimately couples two or more electronic devices.
Now that the wires are formed with or without a second dielectric and second metallization the structure can be filled with a dielectric such as but not limited to epoxy via a molding operation (commonly known in the art) curing the epoxy into a rigid substrate. It would be best to over mold the epoxy beyond the top end points of the formed wires by approximately 25 um-100 um. This permits enough material for a planarization process via grinding, sanding, lapping or other techniques know in the art. In the embodiment of the wires having a second dielectric and second metallization the top tips of the wires may be coated with a temporary coating such as wax or a temporary polymer to prevent metallization from forming at the last 25 um to 100 um (typically) on the second dielectric layer.
Planarization also reveals the tops of the metalized wires providing the opportunity to build up a second circuit layer while electrically coupling said circuit layer to the wires and the base foil. If the tips of the coated wires have been spared from secondary metallization then carefully controlling the planarization of the interconnect substrate in the z-axis will reveal the first metalized layer of the formed wire exposing it to be electrically coupled to the aforementioned second circuit plane formation without coupling the aforementioned optional second metallization of the formed wire to the second circuit plane layer.
The aforementioned second circuit plane layer can then be formed via electro-less plating, Chemical vapor deposition, sputter coating, electro-plating, or any other technique known in the art. This conductive metallization is preferably Cu, Au or any other suitable conductive material and or multiple layers of different materials.
After lifting the interconnect off the smooth substrate. The primary bottom metallic layer, and the secondary top layer may now be formed into discreet circuitry through a traditional photo lithographic etching processes known in the art. The contact points or pads formed through this circuitization process can be additionally plated with suitable metallic alloys for the desired application such as but not limited to wear resistance or solder-ability.
Alternatively, in lieu of a dielectric core in the aforementioned wires a metal core may be substituted through the use of negative 3D printing techniques utilizing but not limited to negative working photo sensitive epoxy known in the art whereby a temporary dielectric is formed through the entire active area of the interconnect except where the core wire metallization is to be formed. Then the metallization is formed through electro-plating, electro-less plating, Chemical vapor deposition, sputter coating or other techniques known in the art to form a sold metallic wire structure. Alternatively, varying metals of varying thicknesses can be formed on the inner walls of the voided structures in the epoxy layers providing the desirable electrical and mechanical properties for the end application. Then the temporary epoxy is removed through stripping techniques known in the art and freestanding metallic wires or tubes remain for continued processing described above.
Alternatively, dielectric cored, metallic cored or metallic tubes with or without additional layers of dielectric and metallization for shielding or coaxial vias could be formed on to discrete metallic pads or circuits pre-formed on to said smooth glass or smooth ceramic or other suitable material through electro-plating, electro-less plating, Chemical vapor deposition, sputter coating or any other technique known in the art. Having their dimensions defined through a temporary photo-lithographic process common in the art. Further, these pads or circuits could be formed utilizing a laser stenciling process whereby a metallic foil is adhered temporarily to the smooth flat base material with an adhesive or wax and the aforementioned techniques for wire formation may be built on top of the discrete pads or circuitry.
Further when the end points of the formed wires are formed discrete pads and or circuitry with varying geometric shapes may be formed based on the intended application of the inter-connect. Solder-able pads or pins of varying shapes for making contact to electrical terminals may be formed and metalized as described previously. This formation and metallization of the end points of the formed wires in one step saves additional processing time and in combination with the formation of the discrete pads on the base metal layer provides the opportunity for flush circuit pads on both ends on the inter-connect once the aforementioned epoxy molding process in completed.
Alternatively, in any of the embodiments described above an elastomer or rubber compound potting material may be substituted for a rigid potting compound providing the interconnect terminals with compliance for mating non-coplanar electronic device surfaces. By varying the durometer of the potting material as well as the formed wires material, thickness, length and shape we may control the total amount of compliance, force and longevity of each of the formed wire mating terminals.
Alternatively, in the event of an aforementioned compliant interconnect a latticework, posts, or a solid block of a suitable hard material such as but not limited to epoxy may be formed within the open spaces of the inter-connect not occupied by the formed wires or the compliant potting material. These structures can be formed through the same 3D printing techniques, in the open spaces of the interconnect body, with a height slightly thinner than the overall thickness of the interconnect (˜10 um to 200 um) providing the interconnect structure with a hard compression stop against the two mating surfaces of the devices intended to be electrically coupled. This will prevent over compression and damage of the interconnect structure.
While presently preferred embodiments have been described for purposes of the disclosure, numerous changes in the arrangement of method steps and those skilled in the art can make apparatus parts. Such changes are encompassed within the spirit of the invention as defined by the appended claims.
Claims
1. An electrical interconnect mechanism comprising:
- two or more discrete contact points such as but not limited to circuit pads within two or more circuit planes; and
- three-dimensional dielectric wires routed between said discrete points on said two or more circuit planes in order to provide electrical coupling of two or more electrical devices through said interconnect mechanism, said dielectric wires having an electrically conductive coating.
2. The interconnect mechanism to claim 1 wherein said circuit planes are substantially parallel to each other.
3. The interconnect mechanism according to claim 1 further comprising outer surfaces of said dielectric wires being metalized for electrically coupling to their respective discrete contact points with any conductive material organic or inorganic.
4. The interconnect mechanism according to claim 3 wherein said conductive material is copper, silver, gold, or conductive polymer.
5. The interconnect mechanism according to claim 3 further comprising placing two or more of said wires placed into intimate contact with one another electrically coupling each other as well as to two or more of said discrete contact pads.
6. The interconnect mechanism according to claim 5 wherein said electrically coupled contact pads may be on opposite sides or on a same side of the structure and the formed metalized wires may originate on one side and terminate on the other or originate and terminate from the same side.
7. The interconnect mechanism according to claim 1 wherein a second coating of dielectric is formed on metalized surfaces of the discrete wires to approximate a coaxial wire.
8. The interconnect mechanism according to claim 1 wherein said formed and metalized dielectric wires are electrically coupled through the metallization process to discrete metallic circuits on the two or more planes or the discrete parallel circuits are formed as an integral part of the formed dielectric wires and then metalized along with the dielectric wires.
9. The interconnect mechanism according to claim 7 wherein the formed second coating of dielectric and metallization of the wires, the second metallization on the coated wire is limited to just short of making contact to the discrete circuit elements on either of said planes.
10. The interconnect mechanism according to claim 9 wherein said metallization is recessed from the discrete circuit elements in are range of 1 um to 50 um.
11. The interconnect mechanism according to claim 1 further comprising the steps of:
- a dielectric wall or plane in the z-axis or vertically in the structure is formed adjacent to the discrete circuit wires instead of forming ground shielding around the discrete circuit wires, transposed between the outer surface circuit planes, metalized with the end points electrically coupled to the discrete circuits patterns on one or both planes.
12. The interconnect mechanism according to claim 11 further comprising said vertical planes are tied to ground to provide for shielding of adjacently routed circuit wires as well as the ability to control the impedance of these wires.
13. The interconnect mechanism according to claim 1 wherein said wires are formed with a core of metal in lieu of dielectric and then a dielectric is coated on them.
14. The interconnect mechanism according to claim 13 wherein said wires are formed with a core of metal in lieu of dielectric and coated with dielectric and then said wires are metalized.
15. The interconnect mechanism according to claim 1 wherein a rigid body is formed between said two or more circuit planes by filling an area between the planes with a dielectric.
16. The interconnect mechanism according to claim 15 wherein said dielectric includes epoxy and air.
17. The interconnect mechanism according to claim 1 wherein said dielectric is epoxy.
18. The interconnect mechanism according to claim 15 wherein said fill material extends to a bottom of the circuit elements making the elements superior.
19. The interconnect mechanism according to claim 15 wherein said fill material extends to a top of the circuit elements making the elements flush to the fill material.
20. The interconnect mechanism according to claim 15 wherein said aforementioned process is repeated with one of the circuit planes of the previously formed interconnect acting as one of the planes for a next sequentially formed build-up circuit plane connected by said formed wires.
21. The interconnect mechanism according to claim 1 wherein a compliant body is formed between said two or more circuit planes by filling an area between the planes with a compliant material to provide alignment of the three dimensional wires and circuitry end points to their desired location as well as allowing for z-axis compliance in order to allow for electrical coupling of two non-coplanar surfaces intended to be coupled by said electrical interconnect mechanism.
22. The interconnect mechanism according to claim 21 wherein said complaint material is an elastomeric material.
23. The interconnect mechanism according to claim 1 further comprising a scaffolding formed in or around the interconnect with a least amount of material in intimate contact with each of the circuit elements on each of the planes transposed between both circuit planes maintaining the z-axis spacing between each plane as well as the x-y location of each of the circuit elements, said scaffolding structure providing the interconnect with a rigid structure while maintaining a greater amount of air around the formed circuits wires.
24. The interconnect mechanism according to claim 23 wherein the greater amount of air can range between 1% and 99% more air than solid epoxy fill within area between said circuit elements.
25. The interconnect mechanism according to claim 23 wherein said least amount of material is epoxy.
26. The interconnect mechanism according to claim 23 wherein there is within or around said interconnect a scaffolding of dielectric, dielectric posts or a solid dielectric block short of the z axis height of the parallel circuit planes wherein penetrations are provided in said scaffolding to permit entry of the wires so that when used in conjunction with a filled elastomeric material, said dielectric structure provides a fixed compression stop of the interconnect structure to prevent damage to the wires due to over compression.
27. The interconnect mechanism according to claim 1 wherein said wires are configured as a free flow of the three dimensionally formed wires by being formed with S curves, cantilevered shapes or coiled shapes to allow for the compliance of the wires while resisting stress cracking in the metal and or dielectric.
28. The interconnect mechanism according to claim 1 wherein a lattice work of non-conductive dielectric scaffolding transposed between the two circuit planes in intimate contact to the circuit elements within the circuit planes is provided which both provides for alignment of the individual contact points or circuit elements within the circuit planes and either providing rigidity for the entire structure or allowing for some compliance of the entire structure in the z-axis, while also allowing for air dielectric around the aforementioned wires.
29. The interconnect mechanism according to claim 1 further comprising two or more terminal points of a electronic component affixed and electrically coupled to the formed wires and the corresponding circuit elements of the corresponding planes, each point coupled to its corresponding designated power, ground, or signal wires and or circuit elements in the interconnect structure so that the electronic component's function is provided to the points of the electrical devices the interconnect is intended to couple.
30. The interconnect mechanism according to claim 29 wherein said electronic component is a capacitor.
31. The interconnect mechanism according to claim 29 wherein said electronic component is a resistor.
32. The interconnect mechanism according to claim 29 wherein said electronic component is an inductor.
33. The interconnect mechanism according to claim 29 wherein the electronic components terminal points are coupled to its corresponding power, ground or signal wires in the interconnect structure so that said component terminal points are provided to the points of the electrical devices the interconnect is intended to couple.
34. The interconnect mechanism according to claim 1 wherein said wires extend beyond a rigid body of the interconnect with shapes conducive for flexing and end points conducive for contacting various shapes of electrical devices acting as a compliant interconnect coupling two non-coplanar electrical devices providing the ability for pitch translation and pin remapping as well as compliant probing in one integrated structure.
35. The interconnect mechanism according to claim 1 wherein said interconnect structure is built with one or more silicon wafer ICs' creating multi chip modules interconnecting the two or more ICs' where a silicon layer is the base circuit plane.
36. The interconnect mechanism according to claim 1 wherein said interconnect structure is built with one or more silicon wafer ICs' creating a redistribution packaging for the IC.
37. The interconnect mechanism according to claim 1 wherein said interconnect structure is built on a flexible circuit base.
Type: Application
Filed: Aug 22, 2018
Publication Date: Feb 14, 2019
Applicant: R&D Circuits, Inc (South Plainfield, NJ)
Inventors: Thomas P. Warwick (Melbourne, FL), Dhananjaya Turpuseema (Whitehouse Station, NJ), James V. Russell (Basking Ridge, NJ)
Application Number: 16/108,527