US20090057157A1

US20090057157A1 - EFAB Methods Including Controlled Mask to Substrate Mating

Info

Publication number: US20090057157A1
Application number: US12/203,776
Authority: US
Inventors: Jeffery A. Thompson
Original assignee: Microfabrica Inc
Current assignee: Microfabrica Inc
Priority date: 2003-11-26
Filing date: 2008-09-03
Publication date: 2009-03-05
Also published as: US20050205430A1

Abstract

Embodiments include treatment of substrates, formation of structures, and formation of multilayer structures using contact masks where a controlled mating of the contact masks and substrates is used. Some embodiments involve controlled mating at speeds equal to or less than 10 microns/second, more preferably equal to or less than 5 microns/second, and even more preferably equal to or less than 1 micron/second. Some embodiments involve controlled mating that uses a higher speed of approach when further away followed by a slower speed of approach to cause mating. Some embodiments involve controlled mating that uses a higher speed of approach when making preliminary contact, then backing away a desired distance, and then making a mating approach that causes mating while using a slower mating speed.

Description

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No. 10/997,709 (Microfabrica Docket No. P-US125-A-MF), filed Nov. 24, 2008 which in turn claims benefit of U.S. Provisional Patent Application No. 60/525,797, filed Nov. 26, 2003. These applications are incorporated herein by reference as if set forth in full.

FIELD OF THE INVENTION

The present invention relates generally to the field of Electrochemical Fabrication and the associated formation of three-dimensional structures (e.g. microscale or mesoscale structures). In particular, it relates to methods and apparatus for forming such three-dimensional structures using contact masks to control selective deposition locations wherein the mating of the masks and substrate occur in a controlled manner.

BACKGROUND OF THE INVENTION

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. It is being commercially pursued by Microfabrica® Inc. (formerly MEMGen Corporation) of Van Nuys, 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 Microfabrica® Inc. (formerly MEMGen Corporation) of Van Nuys, 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 multilayer 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:
(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, p 161, August 1998.
(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, p 244, January 1999.
(3) A. Cohen, “3-D Micromachining by Electrochemical Fabrication”, Micromachine Devices, March 1999.
(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., April 1999.
(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.
(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.
(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.
(8) A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19 of The MEMS Handbook, edited by Mohamed Gad-EI-Hak, CRC Press, 2002.
(9) Microfabrication—Rapid Prototyping's Killer Application”, pages 1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June 1999.
The disclosures of these nine publications are hereby incorporated herein by reference as if set forth in full herein.
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:
1. Selectively depositing at least one material by electrodeposition upon one or more desired regions of a substrate.
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.
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.
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.
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.
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.
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.
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.
An example of a CC mask and CC mask plating are shown in FIGS. 1A-1C. FIG. 1A 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. 1A 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 26 a and 26 b in the insulator as shown in FIG. 1B. After deposition, the CC mask is separated, preferably non-destructively, from the substrate 6 as shown in FIG. 1C. 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.
Another example of a CC mask and CC mask plating is shown in FIGS. 1D-1F. FIG. 1D shows an anode 12′ separated from a mask 8′ that comprises a patterned conformable material 10′ and a support structure 20. FIG. 1D also depicts substrate 6 separated from the mask 8′. FIG. 1E illustrates the mask 8′ being brought into contact with the substrate 6. FIG. 1F illustrates the deposit 22′ that results from conducting a current from the anode 12′ to the substrate 6. FIG. 1G 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.
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.
An example of the electrochemical fabrication process discussed above is illustrated in FIGS. 2A-2F. 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. 2A, 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. 2B. FIG. 2C 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. 2D. 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. 2E. The embedded structure is etched to yield the desired device, i.e. structure 20, as shown in FIG. 2F.
Various components of an exemplary manual electrochemical fabrication system 32 are shown in FIGS. 3A-3C. 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. 3A to 3C 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.
The CC mask subsystem 36 shown in the lower portion of FIG. 3A 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.
The blanket deposition subsystem 38 is shown in the lower portion of FIG. 3B 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.
The planarization subsystem 40 is shown in the lower portion of FIG. 3C and includes a lapping plate 52 and associated motion and control systems (not shown) for planarizing the depositions.
Another method for forming microstructures from electroplated metals (i.e. using electrochemical fabrication techniques) is taught in U.S. Pat. No. 5,190,637 to Henry Guckel, entitled “Formation of Microstructures by Multiple Level Deep X-ray Lithography with Sacrificial Metal layers. This patent teaches the formation of metal structure utilizing mask exposures. A first layer of a primary metal is electroplated onto an exposed plating base to fill a void in a photoresist, the photoresist is then removed and a secondary metal is electroplated over the first layer and over the plating base. The exposed surface of the secondary metal is then machined down to a height which exposes the first metal to produce a flat uniform surface extending across the both the primary and secondary metals. Formation of a second layer may then begin by applying a photoresist layer over the first layer and then repeating the process used to produce the first layer. The process is then repeated until the entire structure is formed and the secondary metal is removed by etching. The photoresist is formed over the plating base or previous layer by casting and the voids in the photoresist are formed by exposure of the photoresist through a patterned mask via X-rays or UV radiation.
Even though electrochemical fabrication as taught and practiced to date, has greatly enhanced the capabilities of microfabrication, and in particular added greatly to the number of metal layers that can be incorporated into a structure and to the speed and simplicity in which such structures can be made, room for enhancing the state of electrochemical fabrication exists. For example, as contact mask size (e.g. area) increases, reliable mating of the mask to a substrate can become more difficult or less reliable. As such, a need exists for techniques that enhance the reliability of mating masks with substrates. In some EFAB microfabrication implementations, failure to reliably mate masks and substrates can result in the presence of thin depositions of sacrificial material between portions of consecutive layers where structural material should bond to structural material which in turn can result in interlayer adhesion failures when sacrificial material is removed In other embodiments, thin depositions of structural material can exist in regions that are intended to be occupied by sacrificial material which in turn can result in difficulties in removing sacrificial material and/or unintended electrical shorting between what would otherwise be isolated structural material portions of a structure, part, or device.

SUMMARY OF THE INVENTION

It is an object of some aspects of the invention to provide a technique for forming microscale or mesoscale single layer or multilayer structures using electrochemical fabrication techniques that provide more reliable mating of masks to substrates (i.e. to an initial substrate or to a substrate that has been modified by the addition of previously formed layers.
It is an object of some aspects of the invention to provide a technique for forming microscale or mesoscale single layer or multilayer structures using electrochemical fabrication techniques with reduced susceptibility to inadvertent material deposition in regions that are intended to be masked.
It is an object of some aspects of the invention to provide a technique for forming microscale or mesoscale multilayer structures using electrochemical fabrication techniques that result in improved layer-to-layer adhesion.
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 teachings herein, may address one or more of the above objects alone or in combination, or alternatively may address some other object of the invention ascertained from the teachings herein. It is not necessarily intended that all objects be addressed by any single aspect of the invention even though that may be the case with regard to some aspects.
In a first aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) forming and adhering a layer of material to a substrate, wherein the substrate may include one or more previously formed layers; (b) repeating the forming and adhering operation of (a) a plurality of times to build up a three-dimensional structure from a plurality of adhered layers; wherein the formation of each of at least a plurality of layers, includes: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when the surfaces are farther apart; (ii) depositing the first material onto the substrate with the contact mask in place; (iii) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the deposited first material or of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when they are farther apart; (ii) etching into the first material with the contact mask in place to form at least one void; and (iii) separating the contact mask and the first material.
In a second aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) forming and adhering a layer of material to a substrate, wherein the substrate may include previously formed layers; (b) repeating the forming and adhering operation of (a) a plurality of times to build up a three-dimensional structure from a plurality of adhered layers; wherein the formation of each of at least a plurality of layers, includes: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate into actual or proximal contact while moving at a first relative speed; and thereafter (ii) separating the mating surface of the contact mask and the mating of the substrate by a distance; and thereafter (iii) bringing the mating surface of a contact mask and a mating surface of the substrate together using a second relative speed, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material, wherein the second relative speed is less than the first relative speed; (iv) depositing the first material onto the substrate with the contact mask in place; (v) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the first material into actual or proximal contact while moving at a first relative speed; and thereafter (ii) separating the mating surface of the contact mask and the mating surface of the first material by a distance; and thereafter (iii) bringing the mating surface of the contact mask and a mating surface of the first material together using a second relative speed just prior to contact when moving the mating surfaces closer together in preparation for etching into the first material, wherein the second relative speed is less than the first relative speed; (iv) etching into the first material with the contact mask in place to form at least one void; and (v) separating the contact mask and the first material.
In a third aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) forming and adhering a layer of material to a substrate, wherein the substrate may include previously formed layers; (b) repeating the forming and adhering operation of (a) a plurality of times to build up a three-dimensional structure from a plurality of adhered layers; wherein the formation of each of at least a plurality of layers, includes: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material; (ii) depositing the first material onto the substrate with the contact mask in place; (iii) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the deposited first material together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for etching into the first material; (ii) etching into the first material with the contact mask in place to form at least one void; and (iii) separating the contact mask and the first deposited material.
In a fourth aspect of the invention, a process for forming a multilayer three-dimensional structure, including A process for forming a structure, including: (a) forming and adhering a layer of material to a substrate, including: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when the surfaces are farther apart; (ii) depositing the first material onto the substrate with the contact mask in place; (iii) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the deposited first material or of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when they are farther apart; (ii) etching into the first material with the contact mask in place to form at least one void; and (iii) separating the contact mask and the first material.
In a fifth aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) forming and adhering a layer of material to a substrate, including: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate into actual or proximal contact while moving at a first relative speed; and thereafter (ii) separating the mating surface of the contact mask and the mating of the substrate by a distance; and thereafter (iii) bringing the mating surface of a contact mask and a mating surface of the substrate together using a second relative speed, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material, wherein the second relative speed is less than the first relative speed; (iv) depositing the first material onto the substrate with the contact mask in place; (v) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the first material into actual or proximal contact while moving at a first relative speed; and thereafter (ii) separating the mating surface of the contact mask and the mating surface of the first material by a distance; and thereafter (iii) bringing the mating surface of the contact mask and a mating surface of the first material together using a second relative speed just prior to contact when moving the mating surfaces closer together in preparation for etching into the first material, wherein the second relative speed is less than the first relative speed; (iv) etching into the first material with the contact mask in place to form at least one void; and (v) separating the contact mask and the first material.
In a sixth aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) forming and adhering a layer of material to a substrate including: (1) obtaining a selective pattern of deposition of a first material having at least one void, including at least one of: (a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing includes: (i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material; (ii) depositing the first material onto the substrate with the contact mask in place; (iii) separating the contact mask and the substrate to expose the at least one void; or (b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching includes: (i) bringing a mating surface of a contact mask and a mating surface of the deposited first material together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for etching into the first material; (ii) etching into the first material with the contact mask in place to form at least one void; and (iii) separating the contact mask and the first deposited material.
In a seventh aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when the surfaces are farther apart; and (b) treating exposed portions of the surface of the substrate.
In a eighth aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) bringing a mating surface of a contact mask and a mating surface of the substrate into actual or proximal contact while moving at a first relative speed; and thereafter (b) separating the mating surface of the contact mask and the mating of the substrate by a distance; and thereafter (c) bringing the mating surface of a contact mask and a mating surface of the substrate together using a second relative speed, just prior to contact, when moving the mating surfaces closer together in preparation for treating the substrate, wherein the second relative speed is less than the first relative speed; and (d) treating the substrate with the contact mask in place.
In a ninth aspect of the invention, a process for forming a multilayer three-dimensional structure, including: (a) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for treating the substrate; and (b) treating the substrate with the contact mask in place.
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. Other aspects of the invention may involve apparatus that can be used in implementing one or more of the above method 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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CC mask plating process, while FIGS. 1D-1G schematically depict a side views of various stages of a CC mask plating process using a different type of CC mask.

FIGS. 2A-2F 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.

FIGS. 3A-3C schematically depict side views of various example subassemblies that may be used in manually implementing the electrochemical fabrication method depicted in FIGS. 2A-2F

FIGS. 4A-4I schematically depict the formation of a first layer of a structure using adhered mask plating where the blanket deposition of a second material overlays both the openings between deposition locations of a first material and the first material itself.

FIG. 5 provides block diagram of a process according a first embodiment of the invention where a speed less than about 10 microns/second is used in bringing a substrate and mask into contact in preparation for a selective patterning operation.

FIG. 6 provides a block diagram of a process according a second embodiment of the invention where at least a two different speeds are used in bringing a substrate and mask into contact where a faster speed is used when the separation is large and a slower speed is used just prior to contact.

FIG. 7 provides block diagram of a process according a third embodiment of the invention where at least a two different speeds are used in bringing a substrate and mask into contact where a first higher speed is used to bring the substrate and mask into an initial contact, or approximate contact, after which the substrate and mask are separated, and then brought back into contact at a second speed in preparation for selectively treating portions of the substrate, wherein the second speed is less than the first speed.

FIG. 8 provides a block diagram of a process according to a fourth embodiment of the invention where a multi-layer structure is formed and put to use and where initial mating of the substrate and the mask for forming at least one layer is performed according to one of the first to third embodiments.

FIG. 9 provides a block diagram of a process according to a fifth embodiment of the invention where a structure of extended layer height is formed by separating the mask and the substrate during a deposition operation and where initial mating of the substrate and mask is performed according to one of the first to third embodiments.

FIG. 10 provides a flowchart depicting generalized operations associated with a sixth embodiment of the invention where a multilayer three-dimensional structure is formed and wherein one of the mating processes of the second or third embodiments is used in preparation for performing a selective patterning operation on at least some layers.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form 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 various other patents and 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 from the teachings set forth herein. All of these techniques may be combined with those of the various embodiments of various aspects of the invention to yield enhanced embodiments. Still other embodiments may be derived from combinations of the various embodiments explicitly set forth herein.
FIGS. 4A-4I illustrate various stages in the formation of a single layer of a multilayer 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. 4A, a side view of a substrate 82 is shown, onto which patternable photoresist 84 is cast as shown in FIG. 4B. In FIG. 4C, 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. 4D, a metal 94 (e.g. nickel) is shown as having been electroplated into the openings 92(a)-92(c). In FIG. 4E, 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. 4F, 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. 4G 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 and sets a thickness for the first layer. In FIG. 4H the result of repeating the process steps shown in FIGS. 4B-4G several times to form a multilayer structure are shown where each layer consists of two materials. For most applications, one of these materials is removed as shown in FIG. 4I to yield a desired 3-D structure 98 (e.g. component or device).
The various embodiments, alternatives, and techniques disclosed herein may form multilayer structures using a single patterning technique on all layers or using different patterning techniques on different layers. For example, different types of patterning masks and masking techniques may be used or even techniques that perform direct selective depositions without the need for masking. For example, mask mating techniques described herein may be used in combination with conformable contact masks and/or nonconformable contact masks and masking operations on some layers while other layers may be formed using other mask types or using contact masks without the modified mating techniques. Proximity masks and masking operations (i.e. operations that use masks that at least partially selectively shield a substrate by their proximity to the substrate even if contact is not made) may be used. Adhered masks and masking operations (masks and operations that use masks that are adhered to a substrate onto which selective deposition or etching is to occur as opposed to only being contacted to it) may be used. In still other embodiments, where multiple selective patterning operations are used on a single layer, those multiple operations may be performed using the same or different patterning techniques.
Non-conformable masks are more fully described in U.S. Provisional Patent Application No. 60/429,484, filed Nov. 26, 2002, by Cohen, et al., and entitled “Non-Conformable Masks and Methods and Apparatus for Forming Three-Dimensional Structures” and U.S. patent application Ser. No. 10/724,513, filed Nov. 26, 2003, by Cohen, et al., and entitled “Non-Conformable Masks and Methods and Apparatus for Forming Three-Dimensional Structures”. These two applications are hereby incorporated herein by reference as if set forth in full.
The masks, masking techniques, and structure formation techniques disclosed explicitly herein may benefit by using the enhanced mask mating techniques disclosed in U.S. patent application Ser. No. 10/724,515, filed Nov. 26, 2003, by Cohen, et al., and entitled “Method for Electrochemically Forming Structures Including Non-Parallel Mating of Contact Masks and Substrates”. This referenced application is incorporated herein by reference as if set forth in full herein. This referenced application teaches the treatment of substrates, formation of structures, and formation of multilayer structures using contact masks where a non-parallel or non-simultaneous mating and/or un-mating of various mask contact surfaces to a substrate surface occurs. Some embodiments involve bringing a relative planar mask contact surface and a relative planar substrate surface together at a small angle (but larger than an alignment tolerance associated with the system). Some embodiments involve flexing a mask to make it non-planar and bringing it into contact with a substrate such that progressively more contact between the mask and substrate occur until complete mating is achieved.
A first embodiment of the invention results in selective treatment of a substrate surface via a patterned contact mask where mating between the mask and the substrate occurs while bringing mating surfaces of the mask and the substrate together at a speed not greater than about 10 microns per second just prior to making initial contact.
FIG. 5 provides block diagram of a process according the first embodiment of the invention. Block 102 calls for the supplying of a contact mask having at least one opening and having a mating surface, while block 104 calls for the supplying of a substrate having a mating surface wherein the substrate is to undergo patterned treatment and where the mating surface of the substrate may be that of a previously deposited material.
Blocks 102 and 104 act as inputs for Block 106 which calls for the moving of the mating surfaces of the mask of block 102 and the substrate of block 104 into contact while they are being relatively moved at a speed of no more than about 10 microns per second, more preferably at a speed no greater than about 5 microns per second, and even more preferably at a speed that is not greater than about 1 micron per second.
Block 108 calls for the selective treatment of those portions of the substrate that are exposed by at least one opening of the mask. The treatment is to occur while the mask and substrate are mated together.
Block 110 calls for the separating of the mask and the substrate from one another. In some embodiments the initial mating surfaces of the mask and the substrate may be separated from one another, either while treatment is ongoing or prior to additional treatment occurring. For example, in such alternative embodiments the treatment may be a deposition operation and the initial mating surfaces of the mask and substrate may be moved apart as the deposit is being built up in such a manner that effective sealing between the side walls of the mask and the side walls of the deposit is maintained. Such controlled separation may be used to enable deposit thicknesses to exceed that allowed by the height of a patterned material that may form the contact portion of the mask. These types of processes for forming extended height structures or high aspect ratio structures may be called electrochemical extrusion processes or ELEX™ processes. Such extrusion processes are more fully described in U.S. patent application Ser. No. 10/271,574 filed Oct. 15, 2002 by Adam Cohen et al and entitled “Methods of and Apparatus for Making High Aspect Ratio Microelectromechanical Structures”. This referenced patent application is hereby incorporated herein by reference as if set forth in full.
In some alternatives to the first embodiment, instead of having the relative speed of approach, just before contact, being set within the specific preferential ranges, a preferential speed of approach or convergence (which may be referred to more simply as a contact speed, mating speed, approach speed, or speed at contact) may be ascertained empirically by those of skill in the art based, for example, based on the performance of mating and deposition experiments where optimal speeds may be selected, interpolated, or extrapolated from those results that give an appropriate balance of plating performance to mating times. Parameters in the experiments may include relative speed of movement between the mask and the substrate, mask area or length and width dimensions, substrate area or length and width dimensions, amount of mask area occupied by voids and/or mating material, mating force or pressure (i.e. a force that may be used in concluding that mating has begun to occur or is complete). As such, in some embodiments of the invention, the mating speed may simply be specified as an effective mating speed that is based at least in part upon experimental results that involved the treatment of at least one or more of the following as variables, overall area of the mask, overall area of the substrate, portion of mask area occupied by voids, portion of mask area occupied by mating surface, and/or relative speed at contact.
The treatment operations of this first embodiment may take on many different forms for accomplishing many different purposes. For example, the treatment operation, as noted above, may be used to form a selective deposit of a material. This deposition process may or may not involve a separating of the substrate and mask. In other embodiments the treatment may comprise an etching operation that operates on a substrate to form one or more selective voids wherein etching operations may be of the electrochemical type or of the chemical type or possibly even of the type that would also bring mechanical forces to bear. Mechanical enhancements may involve the directing of jets of etching material at the substrate, use of vibration, and/or use of abrasive particles that could be directed at the substrate and carried by a liquid (for example, in an etching solution).
The etching operations may be of the selective type (i.e. the type that will not attack all materials potentially present on the substrate within the openings defined by the mask or they may be of a nonselective type (i.e. the type that will attack substantially all materials potentially present within the at least one opening in the mask).
In other embodiments the treatment may result in a roughening of the surface of all or some materials that are exposed by at least one opening in the mask (e.g. via a selective or non-selective microetching operation or via a bombardment with abrasive or chemically active particles).
In still other embodiments the treatment may result in a smoothing of the surface of some or all of the materials exposed by the at least one opening in the mask. For example, this smoothing may be accomplished by an electropolishing process.
In still other embodiments, the treatment may include a cleaning of foreign material from the exposed surfaces of the substrate within the opening(s) in the mask. This cleaning may occur in a variety of ways well known to those of skill in the art. In still other embodiments, the treatment may comprise a selective causing of oxidation or removing of oxidation from the exposed portions of the surfaces of the substrate that are exposed by the at least one opening in the mask. Oxidation may be caused by exposing the surface to an oxygen rich environment at standard or elevated temperatures. Reduction of oxidized material may result, for example, by exposing the surface to a reducing atmosphere or to selected acids. Similarly, in still other embodiments, the treatment may cause selective activation or deactivation of those portions of the substrate surface exposed by the at least one opening in the mask. The activation or deactivation may be appropriate for enabling, or disabling, or encouraging, or discouraging, depositions of material via electroplating processes, electrophoretic processes, electroless deposition processes, and the like, and other processes well known to those of skill in the art.
In still other embodiments, the treatment may include a plurality of treatments. The plurality of treatments may, for example, be selected from those noted above. In still other embodiments other treatment operations may be performed.
A second embodiment of the invention results in selective treatment of a substrate surface via a patterned contact mask where mating between the mask and the substrate occurs via at least a two step process including a relative high speed convergence of the mask and substrate when they are separated by a large distance and a lower speed convergence and contact when they are separated by a smaller distance.
FIG. 6 provides block diagram of a process according the second embodiment of the invention. As with the first embodiment of the invention, the second embodiment provides a treatment to a selective portion of a substrate wherein the treatment may be any of those discussed above in association with the first embodiment or other treatments known to those of skill in the art or even combinations of such treatments. Block 202 of FIG. 6 calls for the supplying of a contact mask similar to that called for by block 102 of FIG. 5. Block 204 of FIG. 6 calls for the supplying of the substrate similar to that called for by block 104 of FIG. 5.
Block 206 calls for bringing the mating surfaces of the mask and the substrate supplied by blocks 202 and 204 into contact with one another. The process of contacting the mating surfaces in this embodiment occurs by moving them closer together using at least a first speed while the mating surfaces are separated by an estimated distance greater than a defined approximate distance and then moving the surfaces into contact while moving at a second speed that is less than the first speed. The first and second speed need not be single speeds but may instead be multiple values of speed.
Block 208 calls for a selective treating of a substrate in an analogous manner to that called for by block 108 in association with FIG. 5.
Block 210 calls for separating the mask and the substrate in an analogous manner to that called for by block 110 associated with FIG. 5.
In some alternatives to the second embodiment, more than two speeds of convergence may be used. For example, a first speed may be used when far away, a second slower speed may be used when somewhat closer, and a third and even slower speed may be used when even closer. In some embodiments, the final speed of relative motion between the substrate and the mask may be similar to those used in the first embodiment (e.g. less than about 10 microns per second, less than about 5 microns per second, and even more preferably less than 1 micron per second just prior to making initial contact. In some alternative embodiments, a preferential speed of contact may be ascertained empirically by those of skill in the art based, for example, on the performance of mating and plating experiments where optimal speeds may be selected from those results that give adequate plating performance along with minimum mating times. Parameters in the experiments may include relative speed of movement between the mask and the substrate, mask area or length and width dimensions, substrate area or length and width dimensions, amount of mask area occupied by voids and/or mating material, mating force or pressure (i.e. a force that may be used in concluding that mating is complete.
A third embodiment of the invention results in selective treatment of a substrate surface via a patterned mask where mating between the mask and the substrate occurs via a three step process where a first higher speed is used to bring the substrate and mask into an initial contact or approximate contact after which the substrate and mask are separated a small amount, and then a second slower speed is used to bring the mask and substrate into final contact (i.e. mating position) in preparation for selectively treating portions of the substrate.
FIG. 7 provides block diagram of a process according the third embodiment of the invention. As with FIGS. 5 and 6, FIG. 7 provides for the selective treatment of a surface of the substrate wherein the treatment operations that may be used are similar to those usable in association with the embodiments of FIGS. 5 and 6.
Block 302 calls for the supplying of a contact mask in a manner analogous to that called for by block 102 of FIG. 5. Block 304 calls for the supplying of a substrate in a matter analogous to that called for by block 104 of FIG. 5.
Block 306 calls for the bringing of the mating surfaces of the mask and the substrate into at least approximate contact, or proximity, where the relative speed between the substrate and the mask, shortly before contact, is equal to or greater than a first speed. Block 308 calls for the separating of the mating surfaces by an approximate desired distance. Block 310 calls for the movement of the mating surfaces into a mating position where the relative speed of motion just prior to mating is less than the first speed.
Blocks 312 and 314 respectively call for the treating of the exposed portion of the substrate and the separation of the mask and the substrate in manners analogous to that called for by blocks 108 and 110 of FIG. 5.
In some alternatives to the third embodiment, during the final approach of the mask and substrate in preparation for treatment operations, a multi-speed approach similar to that of the second embodiment may be used. In still other embodiments approach speeds may fall within the preferential range of the first embodiment or may be derived empirically as noted above.
A fourth embodiment of the invention forms a multi-layer three-dimensional structure where the formation of at least some of the layers use a selective mating and treatment or patterning operation of one of the first to third embodiments or one of their alternatives.
FIG. 8 provides block diagram of a process according the fourth embodiment of the invention. Block 402 calls for the supplying of a substrate which may include one or more completed or partially completed previous layers including one or more deposited materials and it also calls for the supplying of at least one contact mask for performing a selective patterning or treatment operation when forming a multi-layer structure.
Block 404 calls for the bringing of the substrate and at least one of the masks into contact and then patterning the substrate to form at least a portion of a layer, of a multi-layer structure wherein one of the controlled mating processes of the first through third embodiments is used in bringing the substrate and mask into contact (i.e. mated position).
Block 406 calls for completing formation of the layer of the structure as necessary. If the layer formation was completed as a result of the operation of block 404 then block 406 may be skipped. The operation or operations performed under block 406 may take on a variety of forms, for example, selective or blanket depositions of other materials and planarization operations, heat treatment operations, operations to reduce discontinuities and the like, or other operations that will be understood by those of skill in the art.
Block 408 calls for the forming of additional layers of the structure as appropriate so as to complete the formation of the layers of the structure. The formation of these additional layers may involve operations similar to those set out in blocks 404 and 406 or may involve other operations.
Block 410 calls for the performing of any additional necessary post processing operations (i.e. operations that occur after formation of all layers of the structure). The operation or operations called for by block 410 may be considered optional since in some implementations it may not be necessary to perform any post processing operations. Various post processing operations are possible and include, for example; (1) dicing the structure from other structures that were formed simultaneously with it; (2) releasing the structure from any sacrificial material or materials that were used during the formation of layers; (3) separating the structure from the substrate and or attaching the structure to another substrate; (4) coating the structure with any desired material; (5) smoothing discontinuities between layers; (6) performing any annealing, diffusion, bonding, other heat treatment operations, and/or the like.
Block 412 calls for the packaging and connecting of the structure to other structures. This connecting of elements may be considered optional as some implementations may require no such connections. The connections being referred to in this block may be of the functional type or of the physical type or a combination thereof. The other structures to which connection may be made may be, for example, other structures formed on a layer-by-layer basis, or other devices or components not formed on a layer-by-layer basis. Such add-on components may be electrical components, e.g. capacitors, resistors, inductors, or integrated circuits, or the like.
Finally, block 414 calls for the putting of the formed structure to its desired use.
A fifth embodiment of the invention forms a structure of extended layer height by separating the mask and the substrate during a deposition operation where initial mating of the substrate and mask is performed according to one of the first to third embodiments or one of their alternatives.
FIG. 9 provides block diagram of a process according the fifth embodiment of the invention. Block 502 calls for the supplying of a substrate and at least one contact mask in an analogous manner to that of block 402 for FIG. 8.
Block 504 calls for the bringing of the substrate and a mask into contact and the subsequent deposition of material to the substrate where the bringing together involves one of the controlled mating processes of the first through third embodiments.
Block 506 calls for the withdrawing of the mask and the substrate from their initial contact positions either in a continuous or periodic manner. Deposition may continue during movement or it may be stopped prior to movement and then restarted after a step of movement. The deposition and the movement occur in such a way that the side walls of that at least one opening in the mask remain in contact with the deposited material and possibly such that the height of deposition is allowed to grow to a height greater than that allowable without the separating of the mask and the substrate from their initial positions.
Block 508 calls for the forming of any additional layers that are required. The additional layers may be formed using, for example, fixed mask patterning operations and/or using moving mask plating operations. The formation of additional layers is continuous until all layers or levels of the structure are formed.
Blocks 510, 512 and 514 respectively correspond to operations that are analogous to operations 410, 412, and 414 of FIG. 8.
A sixth embodiment of the invention forms a multi-layer structure using the mating operations of the second or third embodiments, or their alternatives, in the formation of at least some layers.
FIG. 10 provides a flowchart depicting generalized operations associated with the sixth embodiment of the invention. The embodiment of FIG. 10 begins with element 602 which calls for the starting of the process. From 602 the process moves forward to block 604 which calls for the defining of a current layer variable “n” and a current operation variable for layer n, “o_n”, the defining of a final layer number as “N” and the defining of a final operation number on layer N as “O_n”.
Next the process moves forward to block 606 which calls for the supplying of the substrate. Then to block 608 which calls for setting “n” to a value of 1 and then to block 610 which calls for setting “o_n” to a value of 1. The substrate in this embodiment, as in the other embodiments, may include previously formed layers, it may include an integrated circuit, other electrically or mechanically functional components, it may be planar or curved, it may be rigid or flexible, and the like.
Next the process moves forward to decision block 622 which inquires as to whether or not variable “o_n” is a selective patterning operation. If the answer is “no”, the process moves forward to element 624 which calls for the performance of operation “o_n”, where after the process moves forward to block 668 which calls for incrementing the variable “o_n” by one. If decision block 622 resulted in a “yes” response, the process moves forward to decision block 626 which inquires as to whether or not variable “o_n” uses a contact mask that is to be carefully mated to the substrate. If the answer to this inquiry is “no” the process moves forward to block 628 which calls for the selective patterning of the substrate. The selective patterning of the substrate may occur in any appropriate manner but does not involve the controlled mating of a contact mask and a substrate using one of the processes set forward in the second embodiment (FIG. 6) or the third embodiment (FIG. 7) or their alternatives. From block 628 the process moves forward to block 668 described herein earlier. If the inquiry of block 626 produces a positive response, the process moves forward to block 630 which calls for supplying a contact mask for performing operation “o_n”.
From block 630 the process moves forward to decision block 642 which inquires as to whether or not the mating involves contacting, backing off and then re-contacting. If this inquiry produces a negative response the process is assumed to proceed according to the mating process of the second embodiment and moves forward to block 644 which calls for moving the mating surfaces of the substrate and mask closer together at a first speed until a known or estimated distance of separation is achieved, and thereafter the process moves forward to block 646 which calls for the moving of the surfaces into contact while moving at a second speed that is less than the first speed. The process then moves forward to block 664 which calls for the selective patterning of exposed portions of the substrate surface while the mask and the substrate are mated.
If the inquiry of block 642 produces a positive response it is assumed that the process proceeds according to the mating process of the third embodiment and moves forward to block 648. Block 648 calls for bringing the mating surfaces of the mask and substrate into at least approximate contact using a relative speed of movement between the substrate and mask, shortly before contact or approximate contact occurs, that is equal to or greater than a first speed. From block 648 the process moves forward to block 650 which calls for separating the mating surfaces by a desired amount (approximately).
From block 650 the process moves forward to block 662 which calls for moving the mating surfaces into a mating position where the relative speed of motion just prior to mating is less than the first speed. From block 662, like block 646, the process moves forward to block 664 which calls for the selective patterning of the exposed portion of the substrate.
From block 664 the process moves forward to block 666 which calls for separating the mask and the substrate. From block 666, like blocks 624 and 628, the process moves forward to block 668 which calls for incrementing “o_n” by one. From block 668 the process moves forward to decision block 670 which inquires as to whether or not the value of variable “o_n” is greater than the value of the final operation “O_n”. A negative response to this inquiry loops the process back to decision block 622 so that additional operations may be performed in association with the production of layer n. A positive response to the inquiry of block 670 causes the process to move forward to block 682 as it is assumed that operations associated with the formation of layer “n” are completed.
Block 682 calls for incrementing variable “n” by one after which the process moves forward to decision block 684. Decision block 684 inquires as to whether the value of the current layer variable “n” is greater than the value of the final layer “N”. If a negative response is produced by this inquiry, the process loops back to block 610 so that operations for producing a next layer may begin. If the inquiry of block 684 is positive, the process moves forward to block 686 as all layers of the structure have been formed.
Block 686 calls for the end of layer formation for the structure. The process of this embodiment ends with the formation of the layers of the structure; however, those of skill in the art will understand that in alternative embodiments post processing operations as set forth in block 410 of FIG. 8, packaging operations as set forth in block 412 of FIG. 8, and/or the putting of the structure to use as set forth in block 414 of FIG. 8 may be implemented.
In the present embodiment, operations “o_n” may take a variety of forms. It is apparent that some such operations may take the form of mating and patterning operations or treatment operations similar to those of second and third embodiments. Other operations may include contact masking operations where controlled mating occurs according to the first embodiment as set forth in FIG. 5. Other operations may include contact masking operations but do not use one of the controlled mating processes of the present application. Still other operations may include adhered mask based patterning operations of the deposition or etching type. Further operations may include planarization operations, cleaning operations, surface activation operations, inspection operations, heat treatment operations, and other operations intended to modify the configuration, surface quality, or structural properties of the layers being formed or those of the structure as a whole.
In the process flowchart for FIG. 10 it is assumed that operations variable “o_n” and layer number variable “n” are numerical values that can be incremented until a final value is reached, in other embodiments, a list of variables may be used where layer transition variables and process end variables are unique values that can be appropriately acted upon without need for an incrementing and a comparison to maximum allowable values.
In some embodiments of the present invention, relative movement between the substrate and the mask may occur by moving the substrate alone, the mask alone, or a combination of the two. Movement may occur by mechanically driven elements, such as rotating screws, rotary motors, linear motors, or the like which cause a fixed amount of motion for a given input. Other driving mechanisms may include bellows type structures or the like which can cause an amount of motion that is pressure sensitive. In some embodiments, either of these types of driving mechanisms may be used while in other embodiments a combination of the two may be used. For example, in some embodiments fixed motion systems may be used to bring the substrate and mask to a given separation while a pressure sensitive motion control system may be used to bring the two into actual contact. This latter approach is particularly useful when a desired mating force or pressure is preferred. In any of these alternatives for causing relative motion between the substrate and the mask, the actual position of the mask and/or the substrate and/or the separation between them may be read from a linear encoder, or the like, which may be included in the system. Similarly, speed of motion may be ascertained by the change in distance read from the linear encoder versus increment of time. For example, in a situation where pressure sensitive control is being used to cause movement, a speed that is determined to be too high or too low may be adjusted by changing the pressure or volume of gas that is feeding or being removed from a bellows.
In some embodiments and particularly in those where conformable masking material is used and more particularly in embodiments where planarity between the mating surfaces may not be absolute, contact may initially occur using only a portion of the masking material which may cause a slowing of mating speed for a given pressure or may require an increase in pressure to maintain a given mating speed. In fact, as the positions of the substrate and mask become closer and closer the flow path to allow removal of any liquid (e.g. plating solution) between the substrate and mask may become so small that a significant resistance to further contacting of the mask and the substrate may develop. This may result in a slowing down of relative motion or even a false sense that mating has occurred. In the present application the speed of motion at mating is preferably the speed of motion just prior to the mask and substrate making initial contact with each other.
In some embodiments the speed of motion at mating may be considered that which exists just prior to an occurrence of a significant change in required force to make an incremental change in position. In some alternative embodiments, where the detection of a slight increase in force per unit of motion may signal the beginning of contact, a relatively fast speed of motion may bring the surfaces to that position, and then a slowing of speed may be implemented at that point. Similarly in embodiments where initial contact is made followed by backing off and then re-contacting, the backing off distance may be based on such a detection of change in force associated with increment of movement.
As noted above, some embodiments may employ diffusion bonding or the like to enhance adhesion between successive layers of material. Various teachings concerning the use of diffusion bonding in electrochemical fabrication processes are set forth in U.S. patent application Ser. No. 10/841,384 which was filed May 7, 2004 by Cohen et al. which is entitled “Method of Electrochemically Fabricating Multilayer Structures Having Improved Interlayer Adhesion” and which is hereby incorporated herein by reference as if set forth in full.
In some embodiments, substrates may include a dielectric material while in other embodiments the layers that are formed may include one or more dielectric materials. Teachings concerning the formation of structures on dielectric substrates and/or the formation of structures that incorporate dielectric materials into the formation process and possibility into the final structures as formed are set forth in a number of patent applications filed on Dec. 31, 2003. The first of these filings is U.S. Patent Application No. 60/534,184, which is entitled “Electrochemical Fabrication Methods Incorporating Dielectric Materials and/or Using Dielectric Substrates”. The second of these filings is U.S. Patent Application No. 60/533,932, which is entitled “Electrochemical Fabrication Methods Using Dielectric Substrates”. The third of these filings is U.S. Patent Application No. 60/534,157, which is entitled “Electrochemical Fabrication Methods Incorporating Dielectric Materials”. The fourth of these filings is U.S. Patent Application No. 60/533,895, which is entitled “Electrochemical Fabrication Method for Producing Multi-layer Three-Dimensional Structures on a Porous Dielectric”. Another filing that deals with dielectric materials as well as mask formation techniques is U.S. patent application Ser. No. 10/841,300 (further particulars of which are set forth in the table below). These patent filings are each hereby incorporated herein by reference as if set forth in full herein.
The patent applications and patents set forth in the following table are hereby incorporated by reference herein as if set forth in full. The teachings in these incorporated applications can be combined with the teachings of the instant application in many ways: For example, enhanced methods of producing structures may be derived from some combinations of teachings, enhanced structures may be obtainable, enhanced apparatus may be derived, and the like.


US Pat App No, Filing Date
US App Pub No, Pub Date	Inventor, Title

10/677,548 - Oct. 1, 2003	Cohen, “Method For Electrochemical Fabrication”
10/677,556 - Oct. 1, 2003	Cohen, “Monolithic Structures Including Alignment
	and/or Retention Fixtures for Accepting Components”
10/830,262 - Apr. 21, 2004	Cohen, “Methods of Reducing Interlayer
	Discontinuities in Electrochemically Fabricated Three-
	Dimensional Structures”
10/271,574 -Oct. 15, 2002	Cohen, “Methods of and Apparatus for Making High
2003-0127336A - Jul. 10, 2003	Aspect Ratio Microelectromechanical Structures”
10/697,597 - Dec. 20, 2002	Lockard, “EFAB Methods and Apparatus Including
	Spray Metal or Powder Coating Processes”
10/677,498 - Oct. 1, 2003	Cohen, “Multi-cell Masks and Methods and Apparatus
	for Using Such Masks To Form Three-Dimensional
	Structures”
10/724,513 - Nov. 26, 2003	Cohen, “Non-Conformable Masks and Methods and
	Apparatus for Forming Three-Dimensional Structures”
10/841,100 - May 7, 2004	Cohen, “Electrochemical Fabrication Methods
	Including Use of Surface Treatments to Reduce
	Overplating and/or Planarization During Formation of
	Multi-layer Three-Dimensional Structures”
10/387,958 - Mar. 13, 2003	Cohen, “Electrochemical Fabrication Method and
2003-022168A - Dec. 4, 2003	Application for Producing Three-Dimensional
	Structures Having Improved Surface Finish“
10/434,494 - May 7, 2003	Zhang, “Methods and Apparatus for Monitoring
2004-0000489A - Jan. 1, 2004	Deposition Quality During Conformable Contact Mask
	Plating Operations”
10/434,289 - May 7, 2003	Zhang, “Conformable Contact Masking Methods and
2004-0065555A - Apr. 8, 2004	Apparatus Utilizing In Situ Cathodic Activation of a
	Substrate”
10/434,294 - May 7, 2003	Zhang, “Electrochemical Fabrication Methods With
2004-0065550A - Apr. 8, 2004	Enhanced Post Deposition Processing Enhanced Post
	Deposition Processing”
10/434,295 - May 7, 2003	Cohen, “Method of and Apparatus for Forming Three-
2004-0004001A - Jan. 8, 2004	Dimensional Structures Integral With Semiconductor
	Based Circuitry”
10/434,315 - May 7, 2003	Bang, “Methods of and Apparatus for Molding
2003-0234179 A - Dec. 25, 2003	Structures Using Sacrificial Metal Patterns”
10/434,103 - May 7, 2004	Cohen, “Electrochemically Fabricated Hermetically
2004-0020782A - Feb. 5, 2004	Sealed Microstructures and Methods of and Apparatus
	for Producing Such Structures”
10/841,006 - May 7, 2004	Thompson, “Electrochemically Fabricated Structures
	Having Dielectric or Active Bases and Methods of and
	Apparatus for Producing Such Structures”
10/434,519 - May 7, 2003	Smalley, “Methods of and Apparatus for
2004-0007470A - Jan. 15, 2004	Electrochemically Fabricating Structures Via Interlaced
	Layers or Via Selective Etching and Filling of Voids”
10/724,515 - Nov. 26, 2003	Cohen, “Method for Electrochemically Forming
	Structures Including Non-Parallel Mating of Contact
	Masks and Substrates”
10/841,300 - May 7, 2004	Lockard, “Methods for Electrochemically Fabricating
	Structures Using Adhered Masks, Incorporating
	Dielectric Sheets, and/or Seed layers That Are
	Partially Removed Via Planarization”
10/841,347 - May 7, 2004	Cohen, “Multi-step Release Method for
	Electrochemically Fabricated Structures”

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 and/or they may not use a planarization process. Some embodiments may not use any selective deposition processes on some or all layers. 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 selective deposition processes or blanket deposition processes on some or all layers that are not electrodeposition processes. Some embodiments may use nickel as a structural material while other embodiments may use one or more different 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 the anode (used during electrodeposition) may be different from a 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.
Some embodiments may employ mask based selective etching operations in conjunction with blanket deposition operations in formation of layers. Some embodiments may form structures on a layer-by-layer basis but deviate from a strict planar layer on planar layer build up process in favor of a process that interlaces material deposited on some or all layers. Such alternative build processes are more fully described in U.S. application Ser. No. 10/434,519, filed on May 7, 2003, entitled “Methods of and Apparatus for Electrochemically Fabricating Structures Via Interlaced Layers or Via Selective Etching and Filling of Voids” which is herein incorporated by reference as if set forth in full.
In still other alternative embodiments, various combinations of elements taught herein in association with one embodiment or alternatives to that embodiment may be combined with elements from other embodiments or alternatives.
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. A process for forming a multilayer three-dimensional structure, comprising:

(a) forming and adhering a layer of material to a substrate, wherein the substrate may include one or more previously formed layers;

(b) repeating the forming and adhering operation of (a) a plurality of times to build up a three-dimensional structure from a plurality of adhered layers;

wherein the formation of each of at least a plurality of layers, comprises:

(1) obtaining a selective pattern of deposition of a first material having at least one void, comprising at least one of:

(a) selectively depositing a first material onto the substrate such that at least one void remains, wherein the depositing comprises:

(i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when the surfaces are farther apart;

(ii) depositing the first material onto the substrate with the contact mask in place;

(iii) separating the contact mask and the substrate to expose the at least one void; or

(b) depositing a first material onto the substrate and selectively etching the deposit of the first material to form at least one void therein, wherein the etching comprises:

(i) bringing a mating surface of a contact mask and a mating surface of the deposited first material or of the substrate together using a relative speed, just prior to contact, which is less than a speed used in moving the mating surfaces closer together when they are farther apart;

(ii) etching into the first material with the contact mask in place to form at least one void; and

(iii) separating the contact mask and the first material.

2. The process of claim 1 wherein the formation of each of a plurality of layers additionally comprises at least one planarization operation.

3. The process of claim 1 wherein the formation of each of a plurality of layers additionally comprises deposition of at least a second material.

4. A process for forming a multilayer three-dimensional structure, comprising:

(a) forming and adhering a layer of material to a substrate, wherein the substrate may include previously formed layers;

wherein the formation of each of at least a plurality of layers, comprises:

(i) bringing a mating surface of a contact mask and a mating surface of the substrate into actual or proximal contact while moving at a first relative speed; and thereafter

(ii) separating the mating surface of the contact mask and the mating of the substrate by a distance; and thereafter

(iii) bringing the mating surface of a contact mask and a mating surface of the substrate together using a second relative speed, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material, wherein the second relative speed is less than the first relative speed;

(iv) depositing the first material onto the substrate with the contact mask in place;

(v) separating the contact mask and the substrate to expose the at least one void; or

(i) bringing a mating surface of a contact mask and a mating surface of the first material into actual or proximal contact while moving at a first relative speed; and thereafter

(ii) separating the mating surface of the contact mask and the mating surface of the first material by a distance; and thereafter

(iii) bringing the mating surface of the contact mask and a mating surface of the first material together using a second relative speed just prior to contact when moving the mating surfaces closer together in preparation for etching into the first material, wherein the second relative speed is less than the first relative speed;

(iv) etching into the first material with the contact mask in place to form at least one void; and

(v) separating the contact mask and the first material.

5. The process of claim 4 wherein the formation of each of a plurality of layers additionally comprises at least one planarization operation.

6. The process of claim 4 wherein the formation of each of a plurality of layers additionally comprises deposition of at least a second material.

7. A process for forming a multilayer three-dimensional structure, comprising:

wherein the formation of each of at least a plurality of layers, comprises:

(i) bringing a mating surface of a contact mask and a mating surface of the substrate together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for depositing a first material;

(i) bringing a mating surface of a contact mask and a mating surface of the deposited first material together using a relative speed that is not greater than about ten microns per second, just prior to contact, when moving the mating surfaces closer together in preparation for etching into the first material;

(iii) separating the contact mask and the first deposited material.

8. The process of claim 7 wherein the relative speed is not greater than about five microns per second.

9. The process of claim 7 wherein the relative speed is not greater than about one micron per second.

10. The process of claim 7 wherein the formation of a plurality of layers additionally comprises at least one planarization operation.

11. The process of claim 7 wherein the formation of each of a plurality of layers additionally comprises deposition of at least a second material.