|Publication number||US20080105557 A1|
|Application number||US 11/927,603|
|Publication date||May 8, 2008|
|Filing date||Oct 29, 2007|
|Priority date||May 7, 2002|
|Also published as||EP1576206A2, EP1576206A3, US20040004001, US20070202693, WO2003095707A2, WO2003095707A3|
|Publication number||11927603, 927603, US 2008/0105557 A1, US 2008/105557 A1, US 20080105557 A1, US 20080105557A1, US 2008105557 A1, US 2008105557A1, US-A1-20080105557, US-A1-2008105557, US2008/0105557A1, US2008/105557A1, US20080105557 A1, US20080105557A1, US2008105557 A1, US2008105557A1|
|Inventors||Adam Cohen, Gang Zhang|
|Original Assignee||Microfabrica Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (7), Classifications (48), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a continuation of U.S. patent application Ser. No. 11/668,299, filed Jan. 29, 2007, which in turn is a continuation of U.S. patent application Ser. No. 10/434,295 filed on May 7, 2003 which claims benefit of U.S. Provisional Patent Application No. 60/379,133, filed on May 7, 2002. These applications are hereby incorporated herein by reference as if set forth in full.
This invention relates to the field of electrochemical deposition and more particularly to the field of electrochemical fabrication which involving electrochemical deposition of one or more materials according to desired cross-sectional configurations so as to build up three-dimensional structures from a plurality of at least partially adhered layers of deposited material. More particularly the invention relates to the integration of multilayer electrochemically fabricated structures with semiconductor circuitry and in particular to the formation of such multilayer structures on integrated circuits.
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 MEMGenŽ 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. 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
Another example of a CC mask and CC mask plating is shown in
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
Various components of an exemplary manual electrochemical fabrication system 32 are shown in
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 sets forth a process for integrating EFAB production with integrated circuits. In this process the structural EFAB material is plated onto and in electrical contact with aluminum contact pads on the integrated circuit. These contact pads may be considered primary contact pads and the locations to which contact with the EFAB structural material will be made. In the described process the integrated circuit design is modified to include secondary contact pads (i.e. one or more pads) that are electrically connected to the primary pads but are spaced therefrom by a distance. The secondary contact pads provide connection points for feeding current to the primary contact pads so that the primary pads may function as cathodes during electroplating operations. The process is illustrated in
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 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 in view of these teachings a need remains in the electrochemical fabrication arts for alternative processes and simpler processes for integrating electrochemically fabricated structures with integrated circuits and particularly for processes that allow formation of multilayer electrochemically fabricated structures on and in electrical contact with semiconductor produced circuitry.
It is an object of some embodiments of various aspects of the present invention to provide alternative processes for integrating electrochemically fabricated multilayer structures with integrated circuits.
It is an object of some embodiments of various aspects of the present invention to provide simpler processes for integrating electrochemically fabricated multilayer structures with integrated circuits.
It is an object of some embodiments of various aspects of the present invention to provide simpler processes that allow formation of multilayer electrochemically fabricated structures on and in electrical contact with semiconductor produced circuitry.
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 the substrate, wherein the 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; wherein at least a plurality of the selective depositing operations include: (1) locating a selected mask on a substrate; (2) in presence of a plating solution, conducting an electric current between an anode and the substrate through at least one opening in the selected mask, such that a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and (3) separating the selected mask from the substrate; wherein the substrate includes a semiconductor wafer or single die containing electrical circuitry and having contact pads to which structural material is to connect; and wherein the process of contacting the contact pads with structural material includes treating the wafer or die with a transition treatment and then applying a structural material to the contact pads by application of an electroless plating solution to the contact pads for a sufficient time to form a deposition of desired thickness.
A second 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 the substrate, wherein the 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; wherein at least a plurality of the selective depositing operations include: (1) locating a selected mask on a substrate; (2) in presence of a plating solution, conducting an electric current between an anode and the substrate through at least one opening in the selected mask, such that a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and (3) separating the selected mask from the substrate; wherein the substrate includes a semiconductor wafer or single die containing electrical circuitry and having contact pads to which structural material is to connect; and wherein the process of forming a conductive layer over a surface of the wafer or die includes: (a) shielding at least the contact pads with a shielding material; (b) depositing a sacrificial material to unshielded regions using at least one of direct metallization or direct plating or electroless deposition; (c) removing the shielding after a deposition of the sacrificial material; and (d) depositing a structural material to the contact pads.
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: selectively depositing at least a portion of a layer onto the substrate, wherein the substrate may include previously deposited material; (A) 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; wherein at least a plurality of the selective depositing operations include: (1) locating a selected mask on a substrate; (2) in presence of a plating solution, conducting an electric current between an anode and the substrate through at least one opening in the selected mask, such that a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and (3) separating the selected mask from the substrate; wherein the substrate includes a semiconductor wafer or single die containing electrical circuitry and having contact pads to which structural material is to connect and having regions of dielectric where structural material is to adhere; and wherein the process of contacting the structural material to regions of dielectric material includes depositing a conductive base material, in a patterned or unpatterned formation, depositing structural material to at least selected locations of the base material and, if base material exists in any regions which are not overlaid by structural material, subsequently removing any such base material that is not overlaid.
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 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, and/or additions of various features of one or more embodiments to the aspects presented above as well as provide other configurations, structures, functional relationships, and processes that have not been specifically set forth above.
The various electrochemical fabrication processes used in various embodiments, alternatives, and techniques disclosed herein may be based on conformable contact masks and masking operations, 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).
Various embodiments are directed to techniques for interfacing or integrating the electrochemical fabrication of multi-layer three dimensional structures with semiconductor devices (e.g. integrated circuits) or devices produced by semiconductor manufacturing techniques. In the various embodiments presented hereafter, the semiconductor devices are provided in wafer form or die form and are used as substrates for the electrochemical fabrication build up process. These devices may be supplied with a passivation layer of adequate thickness already applied or such layers may be thickened prior to beginning the integration process.
An integration process of a first preferred embodiment is depicted in
A photoresist layer 122 is applied to the upper surface of the wafer as shown in
A thin layer of copper 126 is deposited over the entire surface as shown in
Next, electrical contact is made to the thin copper coating 126 and thick copper 128 is plated as shown in
Next the applied coatings of copper are planarized to expose the resist 124 overlaying the interface contact pads 104 as shown in
Next, a transition/barrier layer 132 is deposited onto the wafer as shown in
Next, electrical contact is made to the transition/barrier layer and an electrochemical fabrication structural material 134 (e.g., Ni) is plated thickly as shown in
The deposits are again planarized as shown
After again making electrical contact with the deposited metal, the electrochemical fabrication process is performed to build up the multiple layers of the three-dimensional structure. The multilayer deposition process is shown as completed in
Next, all of the deposited copper is removed by etching as indicated in
Various alternatives to this first embodiment are possible. For example, a diffusion barrier layer could be deposited prior to the thin copper deposit 126 but after formation of the patterned resist 124. It could be removed by controlled etching as its surface area would be largely exposed compared to the amount of exposure that a coating between the interface contact pads 104 and the electrochemically fabricated structure would have. Due to this differential in exposure, it is believed that controlled etching may be performed, after layer formation is complete and the sacrificial material has been removed, to remove the barrier/transition layer from the regions of wafer or die not overlaid by the electrochemically fabricated structure without excessive damage to the contact regions between the electrochemically fabricated structure and the wafer or die.
In another alternative embodiment, a barrier layer could be applied prior to the application of the photoresist thereby obviating the need for a potential barrier layer prior to thin copper deposition of
In other alternative embodiments an adhesion transition layer may also be formed at different stages of the process.
In another alternative embodiment the runner and bus pad would not be needed. In this alternative, the interface pad is made larger than the area intended for deposition of the structural material (e.g. Ni). In this alternative, the portion of the interface contact pad 104 that is not covered by the structural material serves as the contact pad (rather than having a remote contact pad). However, since Al metallization used in the integrated circuit device may be attacked by the Cu stripper, etching of the Cu surrounding the structural material may damage the pad near the structural material. Using the runner and remote contact pad avoids this problem. Also this alternative embodiment could benefit from the previous alternative embodiment where the pre-photoresist application of a barrier layer would inhibit the attack.
A second group of embodiments may take an alternative approach to interfacing the wafer 102 to the initial conductive deposits onto which the multiple layers of the structure will be formed.
It is possible that deposition of extra material 148 as performed by the operation that let to the state depicted in
In some alternative embodiments, over depositing sacrificial material with structural material may be avoided or minimized by use of masking operations or other surface treatment operations such that the structural material is essentially selectively deposited. After such selective deposition of structural material, planarization may occur if desired or needed or a subsequent selective or blanket deposition of sacrificial material may occur to increase its height prior to any planarization operation or prior to initiating formation of a subsequent layer of material. In some embodiments, where barrier layers or adhesion layers are applied prior to the plating of structural material into pockets formed in sacrificial material, the mushrooming effect noted above may not be necessary as the presence of the barrier or adhesion layers may provided the required conductivity
In some alternative embodiments, the IC passivation layer may be thickened prior to performing electroless deposition of sacrificial material, e.g., by coating with a patterned polyimide or photoresist. This thickening may be useful in limiting the spread of plated copper from the passivation layer over the edges of the passivation layer and onto the contact pads.
A one variation of a third group of embodiments, is exemplified in
1. Receive a wafer (or single die) 102 from a standard IC fabrication process (
2. Assuming all exposed contact pads 140 are to be contact locations for electrochemical fabrication, an electroless nickel deposition is applied to the contact pads (
3. As shown in
4. Electrical contact is made to the thin plating base 158 and then thick copper 160 is electroplated as shown in
5. As shown in
7. As shown in
9. Finally, if layer 156 was applied and it is conductive, then it must be removed (not shown), e.g., by wet or dry etching. If the barrier was non-conductive it may remain assuming it isn't undesirable in the final device or that it isn't covering contact pads that are needed for other operations. If the barrier layer is conductive and exists between the structural material (e.g. nickel) and the contact pads, reasonable control of the etching process will ensure that no significant damage to the interface occurs as the exposed portions of the barrier are removed.
A fourth group of embodiments may start off by protecting the contact pads with a dielectric masking material, such as a contact mask or adhered mask. While the pads are protected, direct metallization and plating (e.g., using copper) of the surface of the passivation layer may be performed. After this, a contact mask (if used) may be removed and then structural material plated (e.g. nickel). The plating will cover the contact pads once any dielectric gap between the surface of the passivation layer and the contact pads is bridged by the mushrooming deposition of structural material. If no gap exists, then plating to the pads will begin immediately along with the deposition over the passivation layer.
One example embodiment from the fourth group of embodiments uses an adhered mask and is explained with the aid of
In some alternative embodiments, the direct metallization or direct plating process may be replaced by a sputtering process, an electroless deposition process, or the like. In some embodiments it may be possible to use spray metal deposition to achieve an initial layer of conductive material such as one of the processes described in U.S. Provisional Patent Application No. 60/435,324 described herein elsewhere.
In other alternative embodiments, if necessary, some form of intermediate coating may be applied between conductive pads on the IC (e.g. aluminum pads) and the metal (e.g. nickel) to be deposited thereon. Such coatings may include diffusion barrier materials (e.g. TiN, Ta, and/or TaN, and the like) and/or adhesion promoters (e.g. via phosphoric acid anodizing, stannate immersion, zincate immersion, and the like).
A fifth group of embodiments, illustrated in
Though the present embodiments have focused on electrochemically fabricated structures containing a structural material of nickel and a sacrificial material of copper, other embodiments are possible where different structural and/or sacrificial materials are used. Furthermore, interfacing between a wafer or die and electrochemically produced structures utilizing different structural and/or sacrificial materials may occur via the nickel and copper materials exemplified herein or may occur via the different materials according to the generalized applicability of the processes set forth herein to those materials. Still other embodiments will be apparent to those of skill in the art upon review of the teachings herein, such as processes that involves various combinations of the operations used in the different embodiments disclosed herein.
Various alternatives to and variations of the above noted embodiments exist. In some alternative embodiments, the structural material of choice is nickel and the sacrificial material of choice is copper, and in other embodiments other or additional structural materials may be chosen and other or additional sacrificial materials may be chosen.
The patent applications set forth below are hereby incorporated by reference herein as if set forth in full. The gist of each patent application is included in the table to aid the reader in finding specific types of teachings. It is not intended that the incorporation of subject matter be limited to those topics specifically indicated, but instead the incorporation is to include all subject matter found in these applications. 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 the combination of teachings, enhanced structures may be obtainable, enhanced apparatus may be derived, and the like.
U.S. patent application Ser. No. 09/488,142, filed Jan. 20, 2000, and entitled “An Apparatus for Electrochemical Fabrication Comprising A Conformable Mask” is a divisional of the application that led to the above noted '630 patent. This application describes the basics of conformable contact mask plating and electrochemical fabrication including various alternative methods and apparatus for practicing EFAB as well as various methods and apparatus for constructing conformable contact masks.
U.S. Patent Application No. 60/415,374, filed on Oct. 1, 2002, and entitled “Monolithic Structures Including Alignment and/or Retention Fixtures for Accepting Components” is generally directed to permanent or temporary alignment and/or retention structures for receiving multiple components. The structures are preferably formed monolithically via a plurality of deposition operations (e.g. electrodeposition operations). The structures typically include two or more positioning fixtures that control or aid in the positioning of components relative to one another, such features may include (1) positioning guides or stops that fix or at least partially limit the positioning of components in one or more orientations or directions, (2) retention elements that hold positioned components in desired orientations or locations, and (3) positioning and/or retention elements that receive and hold adjustment modules into which components can be fixed and which in turn can be used for fine adjustments of position and/or orientation of the components.
U.S. Patent Application No. 60/464,504, filed on Apr. 21, 2003, and entitled “Methods of Reducing Discontinuities Between Layers of Electrochemically Fabricated Structures” is generally directed to various embodiments providing electrochemical fabrication methods and apparatus for the production of three-dimensional structures from a plurality of adhered layers of material including operations or structures for reducing discontinuities in the transitions between adjacent layers. Some embodiments improve the conformance between a size of produced structures (especially in the transition regions associated with layers having offset edges) and the intended size of the structure as derived from original data representing the three-dimensional structures. Some embodiments make use of selective and/or blanket chemical and/or electrochemical deposition processes, selective and or blanket chemical and/or electrochemical etching process, or combinations thereof. Some embodiments make use of multi-step deposition or etching operations during the formation of single layers.
U.S. Patent Application No. 60/468,979, filed on May 7, 2003, and entitled “EFAB With Selective Transfer Via Instant Mask” is generally directed to three-dimensional structures that are electrochemically fabricated by depositing a first material onto previously deposited material through voids in a patterned mask where the patterned mask is at least temporarily adhered to a substrate or previously formed layer of material and is formed and patterned onto the substrate via a transfer tool patterned to enable transfer of a desired pattern of precursor masking material. In some embodiments the precursor material is transformed into masking material after transfer to the substrate while in other embodiments the precursor is transformed during or before transfer. In some embodiments layers are formed one on top of another to build up multi-layer structures. In some embodiments the mask material acts as a build material while in other embodiments the mask material is replaced each layer by a different material which may, for example, be conductive or dielectric.
U.S. Patent Application No. 60/469,053, filed on May 7, 2003, and entitled “Three-Dimensional Object Formation Via Selective Inkjet Printing & Electrodeposition” is generally directed to three-dimensional structures that are electrochemically fabricated by depositing a first material onto previously deposited material through voids in a patterned mask where the patterned mask is at least temporarily adhered to previously deposited material and is formed and patterned directly from material selectively dispensed from a computer controlled dispensing device (e.g. an ink jet nozzle or array or an extrusion device). In some embodiments layers are formed one on top of another to build up multi-layer structures. In some embodiments the mask material acts as a build material while in other embodiments the mask material is replaced each layer by a different material which may, for example, be conductive or dielectric.
U.S. patent application Ser. No. 10/271,574, filed on Oct. 15, 2002, and entitled “Methods of and Apparatus for Making High Aspect Ratio Microelectromechanical Structures” is generally directed to various embodiments for forming structures (e.g. HARMS-type structures) via an electrochemical extrusion (ELEX™) process. Preferred embodiments perform the extrusion processes via depositions through anodeless conformable contact masks that are initially pressed against substrates that are then progressively pulled away or separated as the depositions thickens. A pattern of deposition may vary over the course of deposition by including more complex relative motion between the mask and the substrate elements. Such complex motion may include rotational components or translational motions having components that are not parallel to an axis of separation. More complex structures may be formed by combining the ELEX™ process with the selective deposition, blanket deposition, planarization, etching, and multi-layer operations of EFAB™.
U.S. Patent Application No. 60/435,324, filed on Dec. 20, 2002, and entitled “EFAB Methods and Apparatus Including Spray Metal or Powder Coating Processes”, is generally directed to techniques for forming structures via a combined electrochemical fabrication process and a thermal spraying process. In a first set of embodiments, selective deposition occurs via conformable contact masking processes and thermal spraying is used in blanket deposition processes to fill in voids left by selective deposition processes. In a second set of embodiments, selective deposition via a conformable contact masking is used to lay down a first material in a pattern that is similar to a net pattern that is to be occupied by a sprayed metal. In these embodiments a second material is blanket deposited to fill in the voids left in the first pattern, the two depositions are planarized to a common level that may be somewhat greater than a desired layer thickness, the first material is removed (e.g. by etching), and a third material is sprayed into the voids left by the etching operation. The resulting depositions in both the first and second sets of embodiments are planarized to a desired layer thickness in preparation for adding additional layers to form three-dimensional structures from a plurality of adhered layers. In other embodiments, additional materials may be used and different processes may be used.
U.S. Patent Application No. 60/429,483, filed on Nov. 26, 2002, and entitled “Multi-cell Masks and Methods and Apparatus for Using Such Masks to Form Three-Dimensional Structures” is generally directed to multilayer structures that are electrochemically fabricated via depositions of one or more materials in a plurality of overlaying and adhered layers. Selectivity of deposition is obtained via a multi-cell controllable mask. Alternatively, net selective deposition is obtained via a blanket deposition and a selective removal of material via a multi-cell mask. Individual cells of the mask may contain electrodes comprising depositable material or electrodes capable of receiving etched material from a substrate. Alternatively, individual cells may include passages that allow or inhibit ion flow between a substrate and an external electrode and that include electrodes or other control elements that can be used to selectively allow or inhibit ion flow and thus inhibiting significant deposition or etching.
U.S. Patent Application No. 60/429,484, filed on Nov. 26, 2002, and entitled “Non-Conformable Masks and Methods and Apparatus for Forming Three-Dimensional Structures” is generally directed to electrochemical fabrication used to form multilayer structures (e.g. devices) from a plurality of overlaying and adhered layers. Masks, that are independent of a substrate to be operated on, are generally used to achieve selective patterning. These masks may allow selective deposition of material onto the substrate or they may allow selective etching of a substrate whereafter the created voids may be filled with a selected material that may be planarized to yield in effect a selective deposition of the selected material. The mask may be used in a contact mode or in a proximity mode. In the contact mode the mask and substrate physically mate to form substantially independent process pockets. In the proximity mode, the mask and substrate are positioned sufficiently close to allow formation of reasonably independent process pockets. In some embodiments, masks may have conformable contact surfaces (i.e. surfaces with sufficient deformability that they can substantially conform to surface of the substrate to form a seal with it) or they may have semi-rigid or even rigid surfaces. Post deposition etching operations may be performed to remove flash deposits (thin undesired deposits).
U.S. patent application Ser. No. 10/309,521, filed on Dec. 3, 2002, and entitled “Miniature RF and Microwave Components and Methods for Fabricating Such Components” is generally directed to RF and microwave radiation directing or controlling components that may be monolithic, that may be formed from a plurality of electrodeposition operations and/or from a plurality of deposited layers of material, that may include switches, inductors, antennae, transmission lines, filters, and/or other active or passive components. Components may include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and/or back filling operations).
U.S. Patent Application No. 60/468,977, filed on May 7, 2003, and entitled “Method for Fabricating Three-Dimensional Structures Including Surface Treatment of a First Material in Preparation for Deposition of a Second Material” is generally directed to a method of fabricating three-dimensional structures from a plurality of adhered layers of at least a first and a second material wherein the first material is a conductive material and wherein each of a plurality of layers includes treating a surface of a first material prior to deposition of the second material. The treatment of the surface of the first material either (1) decreases the susceptibility of deposition of the second material onto the surface of the first material or (2) eases or quickens the removal of any second material deposited on the treated surface of the first material. In some embodiments the treatment of the first surface includes forming a dielectric coating over the surface while the deposition of the second material occurs by an electrodeposition process (e.g. an electroplating or electrophoretic process).
U.S. patent application Ser. No. 10/387,958, filed on Mar. 13, 2003, and entitled “Electrochemical Fabrication Method and Apparatus for Producing Three-Dimensional Structures Having Improved Surface Finish” is generally directed to an electrochemical fabrication process that produces three-dimensional structures (e.g. components or devices) from a plurality of layers of deposited materials wherein the formation of at least some portions of some layers are produced by operations that remove material or condition selected surfaces of a deposited material. In some embodiments, removal or conditioning operations are varied between layers or between different portions of a layer such that different surface qualities are obtained. In other embodiments varying surface quality may be obtained without varying removal or conditioning operations but instead by relying on differential interaction between removal or conditioning operations and different materials encountered by these operations.
U.S. patent application Ser. No. 10/434,494, filed on May 7, 2003, and entitled “Methods and Apparatus for Monitoring Deposition Quality During Conformable Contact Mask Plating Operations” is generally directed to a electrochemical fabrication (e.g. EFAB) processes and apparatus are disclosed that provide monitoring of at least one electrical parameter (e.g. voltage) during selective deposition where the monitored parameter is used to help determine the quality of the deposition that was made. If the monitored parameter indicates that a problem occurred with the deposition, various remedial operations may be undertaken to allow successful formation of the structure to be completed.
U.S. patent application Ser. No. 10/434,289, filed on May 7, 2003, and entitled “Conformable Contact Masking Methods and Apparatus Utilizing In Situ Cathodic Activation of a Substrate” is generally directed to a electroplating processes (e.g. conformable contact mask plating and electrochemical fabrication processes) that includes in situ activation of a surface onto which a deposit will be made. At least one material to be deposited has an effective deposition voltage that is higher than an open circuit voltage, and wherein a deposition control parameter is capable of being set to such a value that a voltage can be controlled to a value between the effective deposition voltage and the open circuit voltage such that no significant deposition occurs but such that surface activation of at least a portion of the substrate can occur. After making electrical contact between an anode, that comprises the at least one material, and the substrate via a plating solution, applying a voltage or current to activate the surface without any significant deposition occurring, and thereafter without breaking the electrical contact, causing deposition to occur.
U.S. patent application Ser. No. 10/434,294, filed on May 7, 2003, and entitled “Electrochemical Fabrication Methods With Enhanced Post Deposition Processing” is generally directed to a electrochemical fabrication process for producing three-dimensional structures from a plurality of adhered layers is provided where each layer comprises at least one structural material (e.g. nickel) and at least one sacrificial material (e.g. copper) that will be etched away from the structural material after the formation of all layers have been completed. A copper etchant containing chlorite (e.g. Enthone C-38) is combined with a corrosion inhibitor (e.g. sodium nitrate) to prevent pitting of the structural material during removal of the sacrificial material. A simple process for drying the etched structure without the drying process causing surfaces to stick together includes immersion of the structure in water after etching and then immersion in alcohol and then placing the structure in an oven for drying.
U.S. patent application Ser. No. 10/434,315, filed on May 7, 2003, and entitled “Methods of and Apparatus for Molding Structures Using Sacrificial Metal Patterns” is generally directed to molded structures, methods of and apparatus for producing the molded structures. At least a portion of the surface features for the molds are formed from multilayer electrochemically fabricated structures (e.g. fabricated by the EFAB™ formation process), and typically contain features having resolutions within the 1 to 100 μm range. The layered structure is combined with other mold components, as necessary, and a molding material is injected into the mold and hardened. The layered structure is removed (e.g. by etching) along with any other mold components to yield the molded article. In some embodiments portions of the layered structure remain in the molded article and in other embodiments an additional molding material is added after a partial or complete removal of the layered structure.
U.S. patent application Ser. No. 10/434,493, filed on May 7, 2003, and entitled “Electrochemically Fabricated Structures Having Dielectric or Active Bases and Methods of and Apparatus for Producing Such Structures” is generally directed to multilayer structures that are electrochemically fabricated on a temporary (e.g. conductive) substrate and are thereafter bonded to a permanent (e.g. dielectric, patterned, multi-material, or otherwise functional) substrate and removed from the temporary substrate. In some embodiments, the structures are formed from top layer to bottom layer, such that the bottom layer of the structure becomes adhered to the permanent substrate, while in other embodiments the structures are form from bottom layer to top layer and then a double substrate swap occurs. The permanent substrate may be a solid that is bonded (e.g. by an adhesive) to the layered structure or it may start out as a flowable material that is solidified adjacent to or partially surrounding a portion of the structure with bonding occurs during solidification. The multilayer structure may be released from a sacrificial material prior to attaching the permanent substrate or it may be released after attachment.
U.S. patent application Ser. No. 10/434,103, filed on May 7, 2003, and entitled “Electrochemically Fabricated Hermetically Sealed Microstructures and Methods of and Apparatus for Producing Such Structures” is generally directed to multilayer structures that are electrochemically fabricated from at least one structural material (e.g. nickel), at least one sacrificial material (e.g. copper), and at least one sealing material (e.g. solder). In some embodiments, the layered structure is made to have a desired configuration which is at least partially and immediately surrounded by sacrificial material which is in turn surrounded almost entirely by structural material. The surrounding structural material includes openings in the surface through which etchant can attack and remove trapped sacrificial material found within. Sealing material is located near the openings. After removal of the sacrificial material, the box is evacuated or filled with a desired gas or liquid. Thereafter, the sealing material is made to flow, seal the openings, and resolidify. In other embodiments, a post-layer formation lid or other enclosure completing structure is added.
U.S. patent application Ser. No. 10/434,497, filed on May 7, 2003, and entitled “Multistep Release Method for Electrochemically Fabricated Structures” is generally directed to multilayer structures that are electrochemically fabricated from at least one structural material (e.g. nickel), that is configured to define a desired structure and which may be attached to a substrate, and from at least one sacrificial material (e.g. copper) that surrounds the desired structure. After structure formation, the sacrificial material is removed by a multi-stage etching operation. In some embodiments sacrificial material to be removed may be located within passages or the like on a substrate or within an add-on component. The multi-stage etching operations may be separated by intermediate post processing activities, they may be separated by cleaning operations, or barrier material removal operations, or the like. Barriers may be fixed in position by contact with structural material or with a substrate or they may be solely fixed in position by sacrificial material and are thus free to be removed after all retaining sacrificial material is etched.
U.S. patent application Ser. No. 10/434,519, filed on May 7, 2003, and entitled “Methods of and Apparatus for Electrochemically Fabricating Structures Via Interlaced Layers or Via Selective Etching and Filling of Voids” is generally directed to multi-layer structures that are electrochemically fabricated by depositing a first material, selectively etching the first material (e.g. via a mask), depositing a second material to fill in the voids created by the etching, and then planarizing the depositions so as to bound the layer being created and thereafter adding additional layers to previously formed layers. The first and second depositions may be of the blanket or selective type. The repetition of the formation process for forming successive layers may be repeated with or without variations (e.g. variations in: patterns; numbers or existence of or parameters associated with depositions, etchings, and or planarization operations; the order of operations, or the materials deposited). Other embodiments form multi-layer structures using operations that interlace material deposited in association with some layers with material deposited in association with other layers.
Various other embodiments 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 selective deposition processes on some layers that are not conformable contact masking processes and are not even electrodeposition processes. Some embodiments may use nickel as a structural material while other embodiments may use different materials such as gold, silver, or any other electrodepositable materials that can be separated from 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 will be enhanced by pulling the conformable contact mask away from the substrate as deposition is occurring in a manner that allows the seal between the conformable portion of the CC mask and the substrate to shift from the face of the conformal material to the inside edges of the conformable material.
In view of the teachings herein, many further embodiments, alternatives in design and uses of the 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.
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|US7848838 *||Jun 25, 2007||Dec 7, 2010||Massachusetts Institute Of Technology||Digital assembler for digital materials|
|US7939944||May 10, 2011||Sandisk Corporation||Semiconductor die having a redistribution layer|
|US8154852 *||Jan 24, 2008||Apr 10, 2012||Meidensha Corporation||Electric double layer capacitor|
|US8212360||Jul 3, 2012||Sandisk Technologies Inc.||Semiconductor die having a redistribution layer|
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|International Classification||H01P11/00, B81B3/00, G01P15/08, H01P3/06, G01P15/125, H01P5/18, H05K3/46, H01P1/202, C25D7/12|
|Cooperative Classification||C23C28/048, C23C28/345, C23C28/34, C23C28/322, C23C28/36, B81C1/00246, B81B2201/042, C25D5/022, G01P15/0802, C23C4/005, H05K3/4647, H01P11/005, H01P5/183, H01P3/06, B81C1/00126, H01P11/00, B81C2203/0735, G01P15/125, H01P1/202, C23C28/00, C23C18/1605, C23C18/1651, C25D1/003, C25D7/123|
|European Classification||H01P5/18C, G01P15/125, G01P15/08A, B81C1/00C2Z, H01P3/06, H01P1/202, H01P11/00, B81C1/00C12F, H01P11/00B3, C25D1/00, C25D5/02B, C25D7/12, C23C28/00, C23C4/00B|
|Feb 6, 2008||AS||Assignment|
Owner name: MICROFABRICA, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COHEN, ADAM L.;ZHANG, GANG;REEL/FRAME:020471/0570;SIGNING DATES FROM 20030911 TO 20030915