|Publication number||US20050067292 A1|
|Application number||US 10/841,006|
|Publication date||Mar 31, 2005|
|Filing date||May 7, 2004|
|Priority date||May 7, 2002|
|Also published as||US20090038948, US20110180410, US20140209470|
|Publication number||10841006, 841006, US 2005/0067292 A1, US 2005/067292 A1, US 20050067292 A1, US 20050067292A1, US 2005067292 A1, US 2005067292A1, US-A1-20050067292, US-A1-2005067292, US2005/0067292A1, US2005/067292A1, US20050067292 A1, US20050067292A1, US2005067292 A1, US2005067292A1|
|Inventors||Jeffrey Thompson, Adam Cohen, Michael Lockard, Dennis Smalley|
|Original Assignee||Microfabrica Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (40), Referenced by (24), Classifications (9), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a continuation-in-part of U.S. patent application Ser. No. 10/434,493 filed on May 7, 2003 which in turn claims benefit of U.S. Provisional Patent Application Nos., 60/442,656, and 60/379,177 filed on Jan. 23, 2003, and May 7, 2002 respectively. These applications are incorporated herein by reference in their entirety.
Various embodiments of some aspects of the present invention relate generally to the field of Electrochemical Fabrication and the associated formation of three-dimensional structures (e.g. parts, objects, components, or devices) via a layer-by-layer build up of deposited materials and to the processing of such structures after layer formation is complete so that the structures are transferred from a build substrate (i.e. temporary substrate) to a structural substrate.
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 Burbank, Calif. under the name EFAB®. This technique was described in U.S. Pat. No. 6,027,630, issued on Feb. 22, 2000. This electrochemical deposition technique allows the selective deposition of a material using a unique masking technique that involves the use of a mask that includes patterned conformable material on a support structure that is independent of the substrate onto which plating will occur. When desiring to perform an electrodeposition using the mask, the conformable portion of the mask is brought into contact with a substrate while in the presence of a plating solution such that the contact of the conformable portion of the mask to the substrate inhibits deposition at selected locations. For convenience, these masks might be generically called conformable contact masks; the masking technique may be generically called a conformable contact mask plating process. More specifically, in the terminology of Microfabrica™ Inc. (formerly MEMGen® Corporation) of Burbank, Calif. such masks have come to be known as INSTANT MASKS™ and the process known as INSTANT MASKING or INSTANT MASK™ plating. Selective depositions using conformable contact mask plating may be used to form single layers of material or may be used to form multi-layer structures. The teachings of the '630 patent are hereby incorporated herein by reference as if set forth in full herein. Since the filing of the patent application that led to the above noted patent, various papers about conformable contact mask plating (i.e. INSTANT MASKING) and electrochemical fabrication have been published:
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:
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. 1(a)-1(c).
Another example of a CC mask and CC mask plating is shown in FIGS. 1(d)-1(f).
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. 2(a)-2(f). These figures show that the process involves deposition of a first material 2 which is a sacrificial material and a second material 4 which is a structural material. The CC mask 8, in this example, includes a patterned conformable material (e.g. an elastomeric dielectric material) 10 and a support 12 which is made from deposition material 2. The conformal portion of the CC mask is pressed against substrate 6 with a plating solution 14 located within the openings 16 in the conformable material 10. An electric current, from power supply 18, is then passed through the plating solution 14 via (a) support 12 which doubles as an anode and (b) substrate 6 which doubles as a cathode.
Various components of an exemplary manual electrochemical fabrication system 32 are shown in FIGS. 3(a)-3(c). The system 32 consists of several subsystems 34, 36, 38, and 40. The substrate holding subsystem 34 is depicted in the upper portions of each of FIGS. 3(a) to 3(c) and includes several components: (1) a carrier 48, (2) a metal substrate 6 onto which the layers are deposited, and (3) a linear slide 42 capable of moving the substrate 6 up and down relative to the carrier 48 in response to drive force from actuator 44. Subsystem 34 also includes an indicator 46 for measuring differences in vertical position of the substrate which may be used in setting or determining layer thicknesses and/or deposition thicknesses. The subsystem 34 further includes feet 68 for carrier 48 which can be precisely mounted on subsystem 36.
The CC mask subsystem 36 shown in the lower portion of
The blanket deposition subsystem 38 is shown in the lower portion of
The planarization subsystem 40 is shown in the lower portion of
In addition to the above teachings, the '630 patent indicates that electroplating methods can be used in combination with insulating materials. In particular it indicates that though the electroplating embodiments described therein have been described with respect to the use of two metals, a variety of materials, e.g., polymers, ceramics and semiconductor materials, and any number of metals can be deposited either by the electroplating methods described above, or in separate processes that occur throughout the electroplating method. It indicates that a thin plating base can be deposited, e.g., by sputtering, over a deposit that is insufficiently conductive (e.g., an insulating layer) so as to enable subsequent electroplating. It also indicates that multiple support materials (i.e. sacrificial materials) can be included in the electroplated element allowing selective removal of the support materials.
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.
A need still exists in the field for enhancing the combinability of conducting materials, dielectric materials, semi-conducting materials, other materials, processed materials, and/or configured materials within the EFAB process. Furthermore, a need exists in the field for combining electrochemically fabricated structures with dielectric bases or substrates, active bases or substrates (bases or substrates having elements that interact with the structure or that serve a purpose other than merely as a mount for the structure), and/or bases or substrates containing contoured structures. A need remains in the field for improved adhesion between bases or substrates and electrochemically fabricated structures. A need remains in the field for extending the range of capabilities, for expanding the range of materials, and processes available for forming desired structures (including their bases or substrates).
It is an object of various aspects of the present invention to supplement electrochemical fabrication techniques to expand the capabilities of electrochemical fabrication process to meet the structural and functional requirements for varying applications and thus to expand the potential applications available to the technology.
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 any one of the above objects alone or in combination, or alternatively may not address any of the objects set forth above but instead address some other object ascertained from the teachings herein. It is not intended that all of these objects be addressed by any single aspect of the invention even though that may be the case with regard to some aspects.
A first aspect of the invention provides an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) selectively depositing at least a portion of a layer onto a temporary substrate, wherein the temporary substrate may include previously deposited material; (B) forming a plurality of layers such that successive layers are formed adjacent to and adhered to previously deposited layers, wherein said forming includes repeating operation (A) a plurality of times; (C) after formation of a plurality of layers, attaching a structural substrate including a dielectric material to at least a portion of a layer of the structure and removing at least a portion of the temporary substrate from the structure.
A second aspect of the invention provides an electrochemical fabrication apparatus for producing a three-dimensional structure from a plurality of adhered layers, the apparatus including: (A) means for selectively depositing at least a portion of a layer onto a temporary substrate, wherein the temporary substrate may include previously deposited material; and (B) means for forming a plurality of layers such that successive layers are formed adjacent to and adhered to previously deposited layers, wherein said forming includes repeating operation (A) a plurality of times; (C) means for attaching a structural substrate including a dielectric material to at least a portion of a layer of the structure and removing at least a portion of the temporary substrate from the structure; and (D) a computer programmed to control the means for contacting, the means for conducting, the means for separating, and the means for attaching, such that the means for attaching is made to operate after formation of a plurality of layers of the structure.
A third aspect of the invention provides an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) selectively depositing at least a portion of a layer onto a first temporary substrate, wherein the first temporary substrate may include previously deposited material; and (B) forming a plurality of layers such that successive layers are formed adjacent to and adhered to previously deposited layers; and (C) after formation of a plurality of layers attaching a second temporary substrate, which includes a dielectric material, to at least a portion of a layer of the structure and removing at least a portion of the first temporary substrate from the structure and then attaching a structural substrate to at least a portion of a layer of the structure that at least partially overlaps a location where the first temporary substrate was attached.
A fourth aspect of the invention provides an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) selectively depositing at least a portion of a layer onto a sacrificial substrate, wherein the temporary substrate may include previously deposited material; (B) forming a plurality of layers such that each successive layer is formed adjacent to and adhered to a previously deposited layer, wherein said forming includes repeating operation (A) a plurality of times; (C) after formation of a plurality of layers attaching a structural substrate, including a plurality of materials and/or a patterned structure, to at least a portion of a layer of the structure and removing at least a portion of the temporary substrate from the structure.
A fifth aspect of the invention provides an electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process including: (A) selectively depositing at least a portion of a layer onto a first temporary substrate, wherein the first temporary substrate may include previously deposited material; and (B) forming a plurality of layers such that successive layers are formed adjacent to and adhered to previously deposited layers; and (C) after formation of a plurality of layers attaching a second temporary substrate, which includes a plurality of materials and/or includes a patterned structure, to at least a portion of a layer of the structure and removing at least a portion of the first temporary substrate from the structure and then attaching a structural substrate to at least a portion of a layer of the structure that at least partially overlaps a location where the first temporary substrate was attached.
A sixth aspect of the invention provides an electrochemical fabrication process for producing a multi-part three-dimensional structure wherein at least one part is produced from a plurality of adhered layers, the process including: (A) forming at least one part of the multi-part structure, including: (1) selectively depositing at least a portion of a layer onto a substrate, wherein the substrate may include previously deposited material; (2) forming a plurality of layers such that successive layers are formed adjacent to and adhered to previously deposited layers, wherein said forming includes repeating operation (1) a plurality of times; (B) supplying at least one additional part of the multi-part structure; (C) attaching the at least one part to the at least one additional part to form the multi-part structure.
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 and/or addition of various features of one or more embodiments. Other aspects of the invention may involve apparatus that is configured to implement 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.
FIGS. 1(a)-1(c) schematically depict side views of various stages of a CC mask plating process, while FIGS. 1(d)-(g) schematically depict a side views of various stages of a CC mask plating process using a different type of CC mask.
FIGS. 2(a)-2(f) schematically depict side views of various stages of an electrochemical fabrication process as applied to the formation of a particular structure where a sacrificial material is selectively deposited while a structural material is blanket deposited.
FIGS. 3(a)-3(c) schematically depict side views of various example subassemblies that may be used in manually implementing the electrochemical fabrication method depicted in FIGS. 2(a)-2(f).
FIGS. 4(a)-4(i) 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.
FIGS. 6(a)-6(c) depict an example of a structure created according to a preferred embodiment of the invention where FIGS. 6(a) and 6(b) depict two different perspective views of the structure while
FIGS. 7(a)-7(o) illustrate the production of the structure of FIGS. 6(a)-6(c) from a plurality of adhered layers according to a preferred embodiment of the invention.
FIGS. 9(a)-9(e) depict the results of various steps during the practice of an embodiment of the invention.
FIGS. 11(a)-11(j) depict the results of various operations performed during the practice of an embodiment of the invention.
FIGS. 13(a)-13(c) schematically depict a process for swapping a structure 702 from a first substrate 704 to a second substrate 706.
FIGS. 13(d) and 13(e) schematically depict side views of structures and substrates having modified configurations for enhancing attachment.
FIGS. 14(a)-14(c) schematically depict a process for modifying a configuration of an attachment layer of a structure to include notches as indicated in
Detailed Description of Embodiments of the Invention
FIGS. 1(a)-1(g), 2(a)-2(f), and 3(a)-3(c) 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 explicitly set forth herein to yield enhanced embodiments. Still other embodiments be may derived from combinations of the various embodiments explicitly set forth herein.
FIGS. 4(a)-4(i) illustrate various stages in the formation of a single layer of a multi-layer fabrication process where a second metal is deposited on a first metal as well as in openings in the first metal where its deposition forms part of the layer. In
Though the embodiments discussed herein are primarily focused on conformable contact masks and masking operations, the various embodiments, alternatives, and techniques disclosed herein may have application to 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), non-conformable masks and masking operations (i.e. masks and operations based on masks whose contact surfaces are not significantly conformable), and 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).
The process continues with operation 104 which calls for the deposition of a layer onto the substrate or onto a previously formed layer that is already on the substrate. The layer deposited, according to certain embodiments of the invention will contain two or more materials one or more of which are patterned to have a desired configuration for the structure being formed and the other one or more materials acting as sacrificial material which will be removed from the structure after layer formation is completed. As preferred embodiments of the invention call for the separation of the structure from the substrate on which it was formed (i.e. the temporary substrate), and as it may be desirable for the substrate to be made from a structural material as opposed to a sacrificial material, in certain embodiments, the first one or more layers deposited on the substrate may be comprised solely of sacrificial material.
Furthermore, in preferred embodiments of the present invention, as the substrate on which structure is formed is not the permanent substrate on which the structure will reside, it is preferred in some embodiments for the first layers deposited (of the structure) to be the last layers of the structure relative to the permanent substrate and the last layers deposited to be the first layers relative to the permanent substrate. In other words, in some embodiments it is desirable for the structure's layers to be deposited in reverse order.
The electrochemical fabrication process used may be similar to the one illustrated in FIGS. 1(a)-1(c) and 2(a)-2(f) or it may be another process set forth in the '630 patent, a process set forth in one of the other previously incorporated publications, a process described in one of the patents or applications that is included in the table of incorporated patents and applications set forth hereafter, or the process may be a combination of various approaches described in these publications, patents, and applications, or the process may be otherwise known or ascertainable by those of skill in the art. Of course portions of the structures may be formed by other three-dimensional modeling or fabrication processes.
After deposition of a layer, the process proceeds to operation 106 in which an inquiry is made as to whether the last layer of the structure has been formed (i.e. the layer that will contact the permanent substrate in certain embodiments of the invention). If the answer is “no”, the process loops back to operation 104 for further depositions. If the answer is “yes”, the process moves forward to operation 108.
Operation 108 calls for the attachment of a permanent substrate (e.g. a dielectric material) to the last deposited layer of the structure. The attachment may occur via an adhesive (e.g. a pressure sensitive adhesive, a heat sensitive adhesive, or a radiation curable adhesive (if the substrate is transmissive of the appropriate radiation). The application of the adhesive may occur in various ways known to those of skill in the art (e.g. spreading, spinning, spraying, and the like). Attachment may alternatively occur via non-adhesive based bonding techniques, e.g. surface melting, sintering, brazing, ultrasonic welding, vibration welding, and the like.
After attaching the permanent substrate and the layers of deposited material together, the process proceeds to operation 110 where a permanent substrate and layers are separated from the temporary substrate and any sacrificial material is removed. The separation process may occur as a natural part of the sacrificial material removal process if one or more layers of sacrificial material are interposed between the temporary substrate and the structural material or if the temporary substrate is made of the sacrificial material or other material that is attacked by an etchant being used to selectively separate the sacrificial and structural materials.
In alternative embodiments, the three tasks set forth in operations 108 and 110 may be performed in varying orders, for example: (1) bonding and then simultaneous separation and removal of sacrificial material, (2) bonding, separation, then removal, (3) simultaneous separation and removal then bonding, (4) removal, bonding, then separation.
FIGS. 6(a)-6(c) depict an example of a structure (e.g. a switch) created according to a preferred embodiment of the invention. Two different perspective views of the structure are shown in FIGS. 6(a) and 6(b) and a side view is shown in FIG. 6(c). The view seen in
FIGS. 7(m) and 7(n) depict the attachment of the permanent substrate 200 to (1) the stack of layers 201-210, (2) the release layer 211, and (3) the temporary substrate 212.
Various alternatives to the above embodiments exist. Even when not molding the substrate around, the sides of at least one layer, it is still possible to use a moldable material and form the substrate from a temporarily flowable material as opposed to a sheet of material. Contact pads and runners may be formed of the structural material and these may extend to desired locations on the surface of the substrate or may even be encapsulated by the substrate material except at desired contact points. A selective partial etching of the sacrificial material may occur before attachment or formation of the permanent substrate. Layers of material may be etched to a depth of less than one layer thickness or more than one layer thickness. In some embodiments, the depth of etching may be such that portions of the structural material may extend completely through the substrate that will be molded so as to form interconnects that protrude from the bottom of the substrate. In embodiments where it is desired to have interconnects extend through the bottom of the substrate, and when such extension does not occur during molding, the back side of the substrate may be planarized until the structural material is exposed. Substrates need not be planar and their lateral extents need not correspond to those of the layers.
If partially etching to a depth of more that one layer thickness, it is preferred that the pattern of structural material remain of fixed pattern, for all but maybe the deepest layer that will be exposed by the partial etching. This will help ensure a more uniform depth of etching since the sacrificial material will not be shielded by regions of extended structural material. However, in embodiments where the depth of etching is less critical or it is determined that a varying structural pattern will yield a desired etching pattern, no such restriction on structural material patterning need exist.
In some embodiments instead of the temporary substrate and permanent substrate being mounted on opposite sides of the deposited layers, the permanent substrate may be mounted in an orientation perpendicular to that of the temporary substrate. In other words, the permanent substrate may be mounted to the sides of a plurality of deposited layers.
In some embodiments, instead of attaching the permanent substrate to the opposite side of the stack of layers relative to the temporary substrate, the temporary substrate may be removed and the permanent substrate bonded in its place. This may occur by having the temporary substrate or its upper most surface formed of a material that can be selectively etched or otherwise removed from the layers of material preferably without damaging either the structural material or sacrificial material of those layers. And after removal, the bottom most layer of the structure would be exposed and the permanent substrate (e.g. dielectric substrate) attached thereto.
When desiring to mount the permanent substrate into the same position occupied by the temporary substrate, in some embodiments it may be desirable to first mount a second temporary substrate on the opposite side of the stack as compared to the first temporary substrate after which the first temporary substrate may be removed, followed by attachment of the permanent substrate, and then followed by the removal of the second temporary substrate. In still other embodiments, the permanent substrate can be mounted on the opposite side of the stack of layers as compared to the substrate on which the layers were formed and the substrate on which the layers were formed can remain.
In some embodiments of the invention, the permanent substrate may not be a dielectric but instead may be of some other material. For example, the permanent substrate might be made of a conductive material that can not be readily electrodeposited.
Though the use of the term “permanent substrate” has been used herein, it should be understood that it is not intended that the permanent substrate must exist throughout the life of the structure but instead that if form part of the structure for at least some portion of its useful life.
In some embodiments of the invention, a sacrificial material may not be used when depositing the layers one upon the other. In some embodiments, formation of layers may be by single or multiple selective depositions and potentially one or more blanket depositions and potentially one or more planarization operations.
Some embodiments of the invention may provide for attachment of electrochemically produced structures (e.g. structures formed using conformable contact masking techniques or adhered masking techniques) to substrates that may include active elements. This is illustrated in the embodiment of FIGS. 9(a)-9(e) where an electrochemically fabricated structure is attached to a piezoelectric element and the combination of the two provide a working piezoelectric device.
Block 406 calls for the supplying of a second component, where the second component will have a desired shape or will be composed of multiple desired materials. The second component will have a surface that can be attached to the surface of the first component as supplied in association with block 402.
Block 404 calls for the formation of one or more layers on the substrate so as to form a first component (i.e. portion) of a device that is to be created. In the process of forming the first component, the component may be partially surrounded by a sacrificial material which will be eventually removed from the component portion of the layers that are formed. The first component will have a surface that is capable of being bonded or otherwise attached to the second component. Both blocks 404 and 406 are the starting points for the operation of block 208.
In block 408 either one or both of the first and second components are prepared for adhesion to the other component by the addition of an adhesive to at least one of the bonding surfaces. Of course in alternative embodiments block 408 may not be part of the process. In some embodiments, for example, an adhesive may be part of the second component that is supplied.
From block 408 the process moves forward to block 410 where the two components are bonded or otherwise attached to one another. This attachment may occur by use of a pressure sensitive adhesive, a hot melt adhesive, or by other means known to those of skill in the art.
The process then moves forward to block 412 where the first component is separated from the substrate on which it was formed.
Then the process moves forward to block 414 where the first component is separated from any sacrificial material that is not to remain part of the final device that is being created.
Next the process moves to block 416 where either additional manufacturing operations may be performed or where the device that was released in the operation of block 414 may be put to use.
In alternative embodiments, the order of operations associated with blocks 414 and 412 may be reversed. In still other embodiments the accomplishment of the operations of blocks 414 and 412 may occur simultaneously. In still further alternative embodiments either one of the operations of blocks 412 or 414 or both of them may occur between the operations of blocks 408 and 410. Various other alternatives will be apparent to those of skill of the art upon reviewing the teachings herein.
In some embodiments of the invention the attached substrate may be a passive device but the structure that is attached to it may include structures having electrochemically fabricated portions and portions fabricated by other deposition or patterning techniques. One or both the portions may include active components. This is illustrated in the embodiment of FIGS. 11(a)-11(j)
FIGS. 11(a)-11(j) illustrate another alternative embodiment of the invention which includes formation of a number of layers using similar operations followed by formation of additional portions of a structure using alternative operations.
In a final functional device, an electric connection through the structural material 304 of
Block 604 calls for the formation of one or more layers (e.g. by Electrochemical Fabrication) using a first process which will form a portion of the device which may be surrounded by a sacrificial material.
Block 606 calls for the use of at least one different deposition process to further build up and pattern the structure. In some embodiments additional electrochemical fabrication operations may be used in completing formation of the structure which will include the unreleased device.
Block 608 calls for the placement of an adhesive on the last layer of the formed structure and/or on a substrate that is going to be bonded to the structure. The use of such adhesive may or may not be necessary depending on the material that the substrate is made from and the process or processes that will be used to cause joining.
Block 610 calls for the formation of the substrate on the last formed layer of the structure or the adherence on the substrate to the last formed layer.
Block 612 calls for the separation of the structure from the original substrate on which it was formed.
Block 614 calls for the separation of the structure from any sacrificial material that is not to remain part of the final device. This separation will result in a release of the device.
Block 616 calls for the performance of any additional fabrication operations or the putting of the device into use. As with the flowchart of
Two additional embodiments are depicted in FIGS. 13(a)-13(e), 14(a)-14(c), and 15(a)-15(f). These two additional embodiments depict substrate swapping techniques that include either enhanced surface area (interlacing) between the structure and the adhered substrate or the formation of features in the structure that allow interlocking with the swapped substrate.
FIGS. 13(a)-13(c) schematically depict a process for swapping a structure 702 from a first substrate 704 to a second substrate 706 where the contact area between the structure and the second substrate is substantially planar and thus no enhanced surface area or interlocking regions exist to aid in improving adhesion.
The modified structure of
In some embodiments, the openings in layer 714′ may have occurred during the layer formation process as a result of modifying the data descriptive of the layer. Alternatively, in other embodiments the holes in layer 714′ may have been made after layer formation was completed by selectively etching holes into a layer 714 at desired locations. Such etching processes may be performed using contact masks or adhered masks. The etching out of sacrificial material 720 on the other hand may occur in bulk if one is not concerned about removing sacrificial material from other regions of the structure. Or alternatively, the etching may occur by use of one or more masks that at least shield regions of sacrificial material that are not to be removed or that also shield the structural material. After the openings are etched into the layer which is to contribute to adhesion, an adhesive or flowable substrate material may be applied and the substrate bonded to the structure or solidified in contact with the structure (which results in bonding).
In some embodiments, it is preferable that the sacrificial material located in regions outside the structural material portions of layer 714 not be etched away prior to occurrence of the bonding operation. Such ordering of bonding and removal of sacrificial material may allow for improved bonding orientation between the substrate and the structure and/or may help limit the movement of adhesive or flowable substrate material into regions surrounding the structure. In other embodiments it maybe preferable to remove the sacrificial material that is external to the structural material regions, for example, as the sacrificial material may be more accessible prior to bonding than after bonding.
In still other embodiments, external region etching may occur prior to bonding simply because the structures being bonded are relatively tolerant to non-uniformities in orientation or exact positioning and/or to the partial or complete filling of voids by flowable substrate material or adhesive. The obtainment of data associated with modifying the last layer of the structure (or even the last several layers of a structure) may be based upon a designer modifying a CAD file descriptive of the desired structure or by a data processing program that performs various Boolean operations (e.g. erosion or expansion operations) which may be based on fixed or user definable sets of parameters (e.g. a fixed grid of attachment locations and sizes which can be overlaid against the exact position of the structural material of the layer or layers). Such data processing operations may be based on structural data that has already been transformed into layer data or it may be based on structural data that remains in a three-dimensional format.
The gripping functionality of the transition region between the structure and the substrate of
Many alternatives to this interlocking approach as well as the increased surface area approach are possible. In either approach, the interlacing or interlocking elements may extend from a fraction of a layer to multiple layers in height. Instead of using an adhesive to bond the substrate and the structure together, flowable substrate material may have been made to fill the openings after which it would be allowed to solidify or otherwise be made to solidify.
In other embodiments the substrate itself could include openings or reentrant features which could assist in the gripping of an adhesive or filler material to it. In still other embodiments the reentrant features may not be such that any feature alone forms a locking pattern between the substrate and the structure but where a combination of two or more such structures result in a locking configuration (e.g. straight holes extending into the structure at different angles).
In still other embodiments, the two elements to be attached may not include a multi-layer structure and a substrate, they may instead include one or more multi-layer structures in combination with one or more other elements or components that may or may not be multi-layer structures, and may or may not be considered substrate-like.
One embodiment for forming interlock enhanced bonded structures may be summarized as follows: (1) obtain a file descriptive of the structure to be formed; (2) modify the data so as to include one or more branches or channels in the last one or more layers and pockets or reentrant structures in one or more layers that immediately proceed the layers that include the channels; (3) form the structure on a first substrate; (4) etch out the branches and pockets of the reentrant openings; (5) apply a flowable material to the surface of the structure that has the branches or channels where the applied flowable material may be an adhesive if a separate substrate will be bonded by it or it may be a solidifiable material that will be cast or otherwise made to take the shape of a desired substrate; (6) bond the substrate and structure using the adhesive or solidify the substrate material so as to form a substrate that is bonded to the structure; and (7) remove any other sacrificial material the remains and release the first substrate from the structure if desired and if not previously removed.
Many further alternative embodiments are possible and additional examples include: (1) the use of a single sacrificial material to fill the openings as well as the regions external to the structure or to use more then two sacrificial materials; (2) formation of the openings in the structural material in such a way that a sacrificial material is not needed to temporarily fill the openings; and/or (3) use of multiple structural materials. The channels or branches leading to the pockets or reentrant features may have any desired length, they may vary in cross-sectional dimension or they may have variable lengths. The pockets or reentrant features need not have a size difference from that of the channels as they may simply be offset from the position of the channels and in this regard they may actually have smaller cross-sectional area; (5) there need not be a one to one correspondence between pockets and channels; (6) the pockets themselves may have different heights, be located at different depths within the structure and or have different cross-sectional dimensions.
In other alternative embodiments, instead of using undercuts or reentrant features that penetrate into the interior of a structural element, it may be possible to form undercuts on the side walls of regions of structural material which undercuts may be filled with a bonding or substrate material and may act as interlocking elements when considered in association with oppositely oriented undercuts on other portions of the structural material.
In some embodiments, multi-layer structures may be formed starting with a “top” layer (i.e. intended last layer) which is formed adjacent to a temporary substrate, or possibly separated from the temporary substrate by one or more layers of sacrificial material and then adding on subsequent layers until the first layer is reached. In these cases substrate swapping may occur directly by attaching the structural (e.g. permanent substrate) to the last formed layer (e.g. intended first layer) and then, if not already done, the temporary substrate can be removed. In some other embodiments, the multi layer structure can be formed starting with the intended first layer which may be formed directly on a temporary substrate or may be spaced from the temporary substrate by a sacrificial material which may or may not be the same as the sacrificial material that forms part of the layers including structural material. The building may proceed from the first layer to the last layer and if desired one or more layers of sacrificial material may be formed above the last layer. The sacrificial material above the last layer may or may not be the same as the sacrificial material used in forming the layers that contain both structural and sacrificial materials. If necessary, a second temporary substrate may be attached to the last layer or the layers above it. The first temporary substrate (i.e. the initial substrate) may then be removed. If any layers of sacrificial material exist below the first layer they may be removed and thereafter a permanent (or structural substrate) may be attached to the first layer, after which the second temporary substrate may be removed along with any sacrificial material that has not yet been removed.
In some embodiments, the structural substrates may be rigid while in others they may be flexible. In still other embodiments, the permanent substrates may be integrated circuits or other electrical components to which attachment may be made by one or more of dielectric adhesives, wire bonds, re-flowed solder contacts, and/or other conductive or dielectric elements.
Many other alternative embodiments will be apparent to those of skill in the art upon reviewing the teachings herein. Further embodiments may be formed from a combination of the various teachings explicitly set forth in the body of this application. Even further embodiments may be formed by combining the teachings set forth explicitly herein with teachings set forth in the following patents and patent applications each of which is hereby incorporated herein by reference:
US Pat App No, Filing Date US App Pub No, Pub Date Inventor, Title 09/493,496 Cohen, Adam L., Method For Electrochemical Fabrication Jan. 28, 2000 10/677,556 Cohen, et al., Monolithic Structures Including Alignment and/or Oct. 1, 2003 Retention Fixtures for Accepting Components Apr. 21, 2004 Cohen, et al., Methods of Reducing Interlayer Discontinuities in Electrochemically Fabricated Three-Dimensional Structures XX/XXX,XXX (Docket P- Lockard, et al., Methods for Electrochemically Fabricating US099-A-MF) Structures Using Adhered Masks, Incorporating Dielectric Sheets, May 7, 2004 and/or Seed layers That Are Partially Removed Via Planarization 10/271,574 Cohen, et al., Methods of and Apparatus for Making High Aspect Oct. 15, 2002 Ratio Microelectromechanical Structures 20030127336 A1 Jul. 10, 2003 10/697,597 Lockard, et al., EFAB Methods and Apparatus Including Spray Dec. 20, 2002 Metal or Powder Coating Processes 10/677,498 Cohen, et al., Multi-cell Masks and Methods and Apparatus for Oct. 1, 2003 Using Such Masks To Form Three-Dimensional Structures 10/724,513 Cohen, et al., Non-Conformable Masks and Methods and Nov. 26, 2003 Apparatus for Forming Three-Dimensional Structures 10/607,931 Brown, et al., Miniature RF and Microwave Components and Jun. 27, 2003 Methods for Fabricating Such Components, XX/XXX,XXX (Docket P- Cohen, et al., Electrochemical Fabrication Methods Including Use US093-A-MF) of Surface Treatments to Reduce Overplating and/or May 7, 2004 Planarization During Formation of Multi-layer Three-Dimensional Structures 10/387,958 Cohen, et al., Electrochemical Fabrication Method and Application Mar. 13, 2003 for Producing Three-Dimensional Structures Having Improved 2003-022168-A1 Surface Finish Structures Having Improved Surface Finish Dec. 4, 2003 10/434,494 Zhang, et al., Methods and Apparatus for Monitoring Deposition May 7, 2003 Quality During Conformable Contact Mask Plating Operations 2004-0000489-A1 Jan. 1, 2004 10/434,289 Gang Zhang, Conformable Contact Masking Methods and May 7, 2003 Apparatus Utilizing In Situ Cathodic Activation of a Substrate 20040065555 Apr. 8, 2004 10/434,294 Gang Zhang, Electrochemical Fabrication Methods With May 7, 2003 Enhanced Post Deposition Processing Enhanced Post Deposition 20040065550 Processing Apr. 8, 2004 10/434,295 Cohen, et al., Method of and Apparatus for Forming Three- May 7, 2003 Dimensional Structures Integral With Semiconductor Based 2004-0004001 Circuitry Jan. 8, 2004 10/434,315 Christopher A. Bang, Methods of and Apparatus for Molding May 7, 2003 Structures Using Sacrificial Metal Patterns 2003-0234179 Dec. 25, 2003 10/434,103 Cohen, et al., Electrochemically Fabricated Hermetically Sealed May 7, 2004 Microstructures and Methods of and Apparatus for Producing 2004-0020782 Such Structures Feb. 5, 2004 XX/XXX,XXX (Docket P- Cohen, et al., Multi-step Release Method for Electrochemically US105-A-MF) Fabricated Structures May 7, 2004 10/434,519 Dennis R. Smalley, Methods of and Apparatus for May 7, 2003 Electrochemically Fabricating Structures Via Interlaced Layers or 2004-0007470 Via Selective Etching and Filling of Voids Jan. 15, 2004 60/533,947 Kumar, et al., Probe Arrays and Method for Making Dec. 31, 2003 10/724,515 Cohen, et al., Method for Electrochemically Forming Structures Nov. 26, 2003 Including Non-Parallel Mating of Contact Masks and Substrates
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 involve the selective deposition of a plurality of different materials on a single layer or on different layers. Some embodiments may use blanket depositions processes that are not electrodeposition processes. Some embodiments may use nickel as a structural material while other embodiments may use different materials such as gold, silver, or any other electrodepositable materials that can be separated from the copper and/or some other sacrificial material. 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 depth of deposition may be enhanced by pulling the conformable contact mask away from the substrate as deposition is occurring in a manner that allows the seal between the conformable portion of the CC mask and the substrate to shift from the face of the conformal material to the inside edges of the conformable material.
In 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.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3909332 *||Jun 4, 1973||Sep 30, 1975||Gen Electric||Bonding process for dielectric isolation of single crystal semiconductor structures|
|US4306925 *||Sep 16, 1980||Dec 22, 1981||Pactel Corporation||Method of manufacturing high density printed circuit|
|US5106461 *||Dec 21, 1990||Apr 21, 1992||Massachusetts Institute Of Technology||High-density, multi-level interconnects, flex circuits, and tape for tab|
|US5190637 *||Apr 24, 1992||Mar 2, 1993||Wisconsin Alumni Research Foundation||Formation of microstructures by multiple level deep X-ray lithography with sacrificial metal layers|
|US5775569 *||Oct 31, 1996||Jul 7, 1998||Ibm Corporation||Method for building interconnect structures by injection molded solder and structures built|
|US5829128 *||Nov 15, 1995||Nov 3, 1998||Formfactor, Inc.||Method of mounting resilient contact structures to semiconductor devices|
|US5891285 *||May 8, 1997||Apr 6, 1999||Tefco International Co., Ltd.||Process for manufacturing electroformed patterns|
|US5917707 *||Nov 15, 1994||Jun 29, 1999||Formfactor, Inc.||Flexible contact structure with an electrically conductive shell|
|US5989994 *||Dec 29, 1998||Nov 23, 1999||Advantest Corp.||Method for producing contact structures|
|US6002179 *||Mar 13, 1998||Dec 14, 1999||Winbond Electronics Corporation||Bonding pad structure for integrated circuit (I)|
|US6027630 *||Apr 3, 1998||Feb 22, 2000||University Of Southern California||Method for electrochemical fabrication|
|US6043563 *||Oct 20, 1997||Mar 28, 2000||Formfactor, Inc.||Electronic components with terminals and spring contact elements extending from areas which are remote from the terminals|
|US6166915 *||Jan 29, 1997||Dec 26, 2000||Micron Technology, Inc.||Electronic circuits and circuit boards|
|US6255126 *||Dec 2, 1998||Jul 3, 2001||Formfactor, Inc.||Lithographic contact elements|
|US6268015 *||Dec 2, 1998||Jul 31, 2001||Formfactor||Method of making and using lithographic contact springs|
|US6287891 *||Apr 5, 2000||Sep 11, 2001||Hrl Laboratories, Llc||Method for transferring semiconductor device layers to different substrates|
|US6359454 *||Aug 3, 1999||Mar 19, 2002||Advantest Corp.||Pick and place mechanism for contactor|
|US6491968 *||Dec 29, 1999||Dec 10, 2002||Formfactor, Inc.||Methods for making spring interconnect structures|
|US6572742 *||Jan 20, 2000||Jun 3, 2003||University Of Southern California||Apparatus for electrochemical fabrication using a conformable mask|
|US6586955 *||Feb 27, 2001||Jul 1, 2003||Tessera, Inc.||Methods and structures for electronic probing arrays|
|US6627980 *||Apr 12, 2001||Sep 30, 2003||Formfactor, Inc.||Stacked semiconductor device assembly with microelectronic spring contacts|
|US6672875 *||Dec 29, 1999||Jan 6, 2004||Formfactor, Inc.||Spring interconnect structures|
|US6727579 *||Jun 8, 2000||Apr 27, 2004||Formfactor, Inc.||Electrical contact structures formed by configuring a flexible wire to have a springable shape and overcoating the wire with at least one layer of a resilient conductive material, methods of mounting the contact structures to electronic components, and applications for employing the contact structures|
|US6827584 *||Dec 28, 1999||Dec 7, 2004||Formfactor, Inc.||Interconnect for microelectronic structures with enhanced spring characteristics|
|US7047638 *||Jul 24, 2002||May 23, 2006||Formfactor, Inc||Method of making microelectronic spring contact array|
|US7250101 *||May 7, 2003||Jul 31, 2007||Microfabrica Inc.||Electrochemically fabricated structures having dielectric or active bases and methods of and apparatus for producing such structures|
|US20030127336 *||Oct 15, 2002||Jul 10, 2003||Memgen Corporation||Methods of and apparatus for making high aspect ratio microelectromechanical structures|
|US20030157783 *||Jan 13, 2003||Aug 21, 2003||The Penn State Research Foundation||Use of sacrificial layers in the manufacture of high performance systems on tailored substrates|
|US20030221968 *||Mar 13, 2003||Dec 4, 2003||Memgen Corporation||Electrochemical fabrication method and apparatus for producing three-dimensional structures having improved surface finish|
|US20030222738 *||Dec 3, 2002||Dec 4, 2003||Memgen Corporation||Miniature RF and microwave components and methods for fabricating such components|
|US20030234179 *||May 7, 2003||Dec 25, 2003||Memgen Corporation||Methods of and apparatus for molding structures using sacrificial metal patterns|
|US20040000489 *||May 7, 2003||Jan 1, 2004||University Of Southern California||Methods and apparatus for monitoring deposition quality during conformable contact mask plating operations|
|US20040004001 *||May 7, 2003||Jan 8, 2004||Memgen Corporation||Method of and apparatus for forming three-dimensional structures integral with semiconductor based circuitry|
|US20040007468 *||May 7, 2003||Jan 15, 2004||Memgen Corporation||Multistep release method for electrochemically fabricated structures|
|US20040007470 *||May 7, 2003||Jan 15, 2004||Memgen Corporation||Methods of and apparatus for electrochemically fabricating structures via interlaced layers or via selective etching and filling of voids|
|US20040020782 *||May 7, 2003||Feb 5, 2004||Memgen Corporation||Electrochemically fabricated hermetically sealed microstructures and methods of and apparatus for producing such structures|
|US20040065550 *||May 7, 2003||Apr 8, 2004||University Of Southern California||Electrochemical fabrication methods with enhanced post deposition processing|
|US20040065555 *||May 7, 2003||Apr 8, 2004||University Of Southern California||Conformable contact masking methods and apparatus utilizing in situ cathodic activation of a substrate|
|US20040144653 *||Jan 27, 2003||Jul 29, 2004||Institut National D'optique||Microdevice with movable microplatform and process for making thereof|
|US20050067292 *||May 7, 2004||Mar 31, 2005||Microfabrica Inc.||Electrochemically fabricated structures having dielectric or active bases and methods of and apparatus for producing such structures|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7109118||May 7, 2004||Sep 19, 2006||Microfabrica Inc.||Electrochemical fabrication methods including use of surface treatments to reduce overplating and/or planarization during formation of multi-layer three-dimensional structures|
|US7195989||May 7, 2004||Mar 27, 2007||Microfabrica Inc.||Electrochemical fabrication methods using transfer plating of masks|
|US7250101 *||May 7, 2003||Jul 31, 2007||Microfabrica Inc.||Electrochemically fabricated structures having dielectric or active bases and methods of and apparatus for producing such structures|
|US7271022 *||Apr 11, 2005||Sep 18, 2007||Touchdown Technologies, Inc.||Process for forming microstructures|
|US7488686||Sep 19, 2006||Feb 10, 2009||Microfabrica Inc.||Electrochemical fabrication methods including use of surface treatments to reduce overplating and/or planarization during formation of multi-layer three-dimensional structures|
|US7504840||Oct 6, 2005||Mar 17, 2009||Microfabrica Inc.||Electrochemically fabricated microprobes|
|US7611616||Aug 18, 2006||Nov 3, 2009||Microfabrica Inc.||Mesoscale and microscale device fabrication methods using split structures and alignment elements|
|US7878385||Oct 30, 2007||Feb 1, 2011||Microfabrica Inc.||Probe arrays and method for making|
|US7972491 *||Apr 15, 2005||Jul 5, 2011||Hitachi Metals, Ltd.||Method for imparting hydrogen resistance to articles|
|US8070931||Dec 29, 2008||Dec 6, 2011||Microfabrica Inc.||Electrochemical fabrication method including elastic joining of structures|
|US8262916||Jun 30, 2010||Sep 11, 2012||Microfabrica Inc.||Enhanced methods for at least partial in situ release of sacrificial material from cavities or channels and/or sealing of etching holes during fabrication of multi-layer microscale or millimeter-scale complex three-dimensional structures|
|US8551314||Nov 3, 2009||Oct 8, 2013||Microfabrica Inc.||Mesoscale and microscale device fabrication methods using split structures and alignment elements|
|US8702955||Nov 2, 2011||Apr 22, 2014||Microfabrica Inc.||Electrochemical fabrication method including elastic joining of structures|
|US8753702||Jan 20, 2004||Jun 17, 2014||Fujifilm Dimatix, Inc.||Printing on edible substrates|
|US9053873||Sep 20, 2012||Jun 9, 2015||Harris Corporation||Switches for use in microelectromechanical and other systems, and processes for making same|
|US9053874||Sep 20, 2012||Jun 9, 2015||Harris Corporation||MEMS switches and other miniaturized devices having encapsulating enclosures, and processes for fabricating same|
|US20050023148 *||May 7, 2004||Feb 3, 2005||Microfabrica Inc.||Methods for electrochemically fabricating structures using adhered masks, incorporating dielectric sheets, and/or seed layers that are partially removed via planarization|
|US20050067292 *||May 7, 2004||Mar 31, 2005||Microfabrica Inc.|
|US20050142739 *||Jan 3, 2005||Jun 30, 2005||Microfabrica Inc.||Probe arrays and method for making|
|US20050184748 *||Jan 3, 2005||Aug 25, 2005||Microfabrica Inc.||Pin-type probes for contacting electronic circuits and methods for making such probes|
|US20060006888 *||Sep 24, 2004||Jan 12, 2006||Microfabrica Inc.||Electrochemically fabricated microprobes|
|WO2008064055A2 *||Nov 15, 2007||May 29, 2008||Richard J Baker||Printing, depositing, or coating on flowable substrates|
|WO2013052418A1 *||Oct 1, 2012||Apr 11, 2013||Harris Corporation||Method for making electrical structure with air dielectric and related electrical structures|
|WO2014113508A2||Jan 15, 2014||Jul 24, 2014||Microfabrica Inc.||Methods of forming parts using laser machining|
|U.S. Classification||205/118, 205/170|
|International Classification||B81C1/00, C25D5/02|
|Cooperative Classification||B81C2201/019, B81C2201/0181, B81C1/00373, C25D1/003|
|Oct 18, 2004||AS||Assignment|
Owner name: MICROFABRICA INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:THOMPSON, JEFFREY A.;COHEN, ADAM L.;LOCKARD, MICHAEL S.;AND OTHERS;REEL/FRAME:015898/0646;SIGNING DATES FROM 20040930 TO 20041012