DETAILED DESCRIPTION

[0089] 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 to yield enhanced embodiments. Still other embodiments may be derived from combinations of the various embodiments explicitly set forth herein.

[0090] 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 FIG. 4 ( a ), a side view of a substrate 82 is shown, onto which patternable photoresist 84 is cast as shown in FIG. 4 ( b ). In FIG. 4 ( c ), a pattern of resist is shown that results from the curing, exposing, and developing of the resist. The patterning of the photoresist 84 results in openings or apertures 92 ( a )- 92 ( c ) extending from a surface 86 of the photoresist through the thickness of the photoresist to surface 88 of the substrate 82 . In FIG. 4 ( d ), a metal 94 (e.g. nickel) is shown as having been electroplated into the openings 92 ( a )- 92 ( c ). In FIG. 4 ( e ), the photoresist has been removed (i.e. chemically stripped) from the substrate to expose regions of the substrate 82 which are not covered with the first metal 94 . In FIG. 4 ( f ), a second metal 96 (e.g., silver) is shown as having been blanket electroplated over the entire exposed portions of the substrate 82 (which is conductive) and over the first metal 94 (which is also conductive). FIG. 4 ( g ) depicts the completed first layer of the structure which has resulted from the planarization of the first and second metals down to a height that exposes the first metal and sets a thickness for the first layer. In FIG. 4 ( h ) the result of repeating the process steps shown in FIGS. 4 ( b )- 4 ( g ) several times to form a multi-layer structure are shown where each layer consists of two materials. For most applications, one of these materials is removed as shown in FIG. 4 ( i ) to yield a desired 3-D structure 98 (e.g. component or device).

[0091] The various embodiments, alternatives, and techniques disclosed herein may be used in combination with electrochemical fabrication techniques that use different types of patterning masks and masking techniques. For example, conformable contact masks and masking operations may be used, proximity masks and masking operations (i.e. operations that use masks that at least partially selectively shield a substrate by their proximity to the substrate even if contact is not made) may be used, non-conformable masks and masking operations (i.e. masks and operations based on masks whose contact surfaces are not significantly conformable) may be used, 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) may be used.

[0092] Unless specified otherwise in the various embodiments set forth herein, the following terms shall have the following definitions.

[0093] The “build axis” or “build orientation” is the axis or orientation that is perpendicular to the planes of the layers that are used in building up structures. The build axis points in the direction of layer build up.

[0094] An “up-facing feature” is an element dictated by the cross-sectional data for a given layer “n” and a next layer “n+1” that is to be formed from a given material that exists on the layer “n” but does not exist on the immediately succeeding layer “n+1”. For convenience the term “up-facing feature” will apply to such features regardless of whether the layers are stacked one above the other, one below the other, or along any other orientation of the build axis.

[0095] A “down-facing feature” is an element dictated by the cross-sectional data for a given layer “n” and a preceding layer “n−1” that is to be formed from a given material that exists on layer “n” but does not exist on the immediately preceding layer “n−1”. As with up-facing features, the term “down-facing feature” shall apply to such features regardless of whether the layers are stacked one above the other, one below the other, or along any other oriented build axis.

[0096] A “continuing region” is the portion of a given layer “n” that is dictated by the cross-sectional data for a given layer “n”, a next layer “n+1” and a preceding layer “n−1” that is neither up-facing nor down-facing for that layer “n”.

[0097] Various embodiments of various aspects of the invention are directed to formation of three-dimensional structures from materials some of which are to be electrodeposited. Some of these structures may be formed form a single layer of one or more deposited materials while others are formed from a plurality of layers of deposited materials (e.g. 2 or more layers, more preferably five or more layers, and most preferably ten or more layers). In some embodiments structures having features positioned with micron level precision and minimum features size on the order of tens of microns are to be formed. In other embodiments structures with less precise feature placement and/or larger minimum features may be formed. In still other embodiments, higher precision and smaller minimum feature sizes may be desirable.

[0098] Various embodiments disclosed herein or portions of those embodiments may supplement the above incorporated and known techniques by adding to them (for the formation of any given structure) processes that involve the selective etching of deposited material (e.g. via contact masks, e.g. of the conformable contact type or the non-conformable contact type, or via adhered masks, e.g. of the photoresist type, ablatable type, transfer plated type, ink jet deposited type, or the like) and the filling of created voids with additional materials.

[0099] Various other embodiments of various aspects of the invention, may depart from the selective deposition of materials entirely, and use blanket electrodeposition operations to deposit materials and selective etching operations (e.g. via conformable contact masks, non-conformable contact masks, or via adhered masks) to pattern those materials by creating voids that can be filled in using blanket deposition operations.

[0100] Various other embodiments may cause deposition of material to deviate from a strict layer-by-layer build up process (e.g. where an n ^th layer is completely formed prior to beginning deposition operations for forming a portion of an (n+1) ^th layer) and instead prior to completing the formation of an n ^th layer, a deposition operation for depositing material to form part of a subsequent layer (e.g. (n+1) ^th layer) is initiated.

[0101] In some of these embodiments, etching operations may be used to define at least some outward facing portions of structures (i.e. portions of the structure or component that are not bounded by other structural material or at least other structural material of a particular type) while in other embodiments etching operations may only be used to define internal portions of structural material (i.e. portions which are not out-facing).

[0102] In some embodiments selective etching operations of a deposited material are performed (e.g. by use of a temporary mask which has openings which dictate explicitly where etching will be perform and where etching will not be performed). In some embodiments, an approach may be taken where temporarily applied or positioned masks may shield some regions from attack of a selective etchant but the exact masking pattern does not solely or explicitly determine the exact etching pattern(s), as they are determined, at least in part, by a second material that is not attacked by the etchant which is located adjacent to the material that is to be etched.

[0103] FIG. 5 depicts a block diagram of four basic operations of a simplified embodiment of some aspects of the invention. Block 101 (Operation 1) calls for the deposition of a material. Block 102 (Operation 2) calls for the selective etching of material, e.g. via a conformable contact (CC) mask, a non-conformable contact mask, or an adhered mask). Block 103 (Operation 3) calls for deposition of a material such that it occupies at least a portion of the void created by the etching process of Operation 2. Block 104 (Operation 4) calls for the planarization of at least one of the deposited materials.

[0104] FIG. 6 provides more detail on some of the possible implementations of Operations 1-4. Two examples of how Operation 1 may be implemented are given: (1) blanket deposition, “A.” and (2) selective deposition, e.g. via a contact C mask or an adhered mask), “B.”. Three specific examples of how the blanket deposition, “A.”, may be implemented are indicated: (1) by electroplating, “i”, (2) by electroless plating “ii”, or(3) by electrophoretic plating, “iii”. Other examples include the use of a spray metal deposition technique such as one of the variety of thermal spray metal deposition techniques examples of which have been set forth in U.S. Provisional Patent Application No. 60/435,324. Further examples may include various physical or chemical deposition processes or the like. For example, a powder or metal paste may be applied to the surface. A powder may be spread and then sintered; a paste may be spread and then cured (e.g. a conductive epoxy). A binder material may remain or be removed either prior to or after consolidation.

[0105] Two examples are given on how the selective deposition, “B.”, may be implemented: (1) via a mask (e.g. CC mask) using a trapped volume of plating solution, “i.”, and (2) via a mask using a open volume of plating solution, “ii”. The trapped volume of plaiting solution may be formed by use of a contact mask that includes a solid support that will function as a anode and which in combination with the substrate will define a closed volume of plating solution. The open volume of plating solution may be formed using a contact mask with the patterned material adhered to a porous or at least perforated support from which is spaced an anode such that the volume of plating solution within the opening(s) of the contact mask will not be a closed volume but can communicate with plating solution outside the limited space defined by the patterned mask, the mask support, and the substrate. Alternatively, the creation of an open volume may be implemented by formation of a patterned mask that is adhered to and supported by the substrate itself wherein the volume of plating solution within the voids or openings in the patterned mask material extend directly into a larger volume of plating solution. Such as adhered mask may be, for example, a patterned photoresist, a patterned ablatable material, an electrostatically deposited patterned material, a ink jet deposited patterned material, a pattern transferred from a patterned material, or a pre-patterned material which is temporally supported by a non-pattern support structure and is transferred to the substrate. The “B.i.” and “B.ii.” plating preferably occurs via electroplating, electroless plating, or electrophoretic type plating. Specific implementation details and other alternative implementations for Operation 1 will be apparent to those skilled in the art upon review of the teachings herein.

[0106] Two examples are given on how Operation 2 may be implemented: (1) selective etching by electrochemical etching, “A.”, and (2) selective etching by use of a chemical etchant, “B.”. The selectivity of either of these two alternatives may be obtained using a patterned mask that limits the region on which etching operates. Such masks may be of the trapped volume or open volume type mentioned in conjunction with Operation (1). The electrochemical etching may be performed by electroplating from the substrate (i.e. the substrate functions as the anode) to a cathode. The cathode may be the support for a patterned contact mask or it may be a separate structure, for example, when the patterned mask material is adhered to the substrate or when it is supported by a porous, perforated, or other apertured structure. Two examples for implementing the chemical etching process are indicated: (1) via use of a selective etchant, “i”, and (2) via use of a non-selective etchant. Care may need to be taken when implementing the etching processes. If more than one material is simultaneously exposed to the etchant or etching action, any differential in etching rate must be taken into consideration. If a difference in etching rate can not be tolerated, selective etching operations may need to be broken down into multiple steps such that during any given step only one material is being etched. Specific implementation details and other alternative implementations for Operation 2 will be apparent to those skilled in the art upon review of the teachings herein.

[0107] Two examples of how Operation 3 may be implemented are indicated. The examples given are identical to those given for Operation 1. Various examples for each of the two implementations are also given. These various other examples are also identical to those for Operation 1. As noted above with regard to Operation 1, specific implementation details and other alternative implementations for Operation 3 will be apparent to those skilled in the art upon review of the teachings herein.

[0108] Two examples of implementing Operation 4 are given: (1) mechanical lapping, “A”, and (2) chemical mechanical polishing, “B.”. Specific implementation details and other alternative implementations for Operation 4 will be apparent to those skilled in the art upon review of the teachings herein.

[0109] FIG. 7 depicts a process flowchart for a preferred two material embodiment of some aspects of the invention. Various elements of FIG. 7 are provided with codes that refer back to the operations and alternatives set forth in FIG. 6 . In this embodiment, the process starts with a blanket electroplating operation 202 of a first material onto a substrate. This blanket deposition applies a coating of desired thickness (e.g. somewhat more than one layer thickness), then moves onto a planarization operation 204 of the first material via mechanical lapping to achieve a net deposition that is both uniform and of a known thickness or height (e.g. at or slightly more than one layer thickness).

[0110] The process then proceeds to a selective etching operation 206 of the first material by electrochemical etching (e.g. reversed electroplating using a contact mask or adhered masks). The electrochemical etching is controlled to give a desired depth of etching. The depth of etching may be targeted to be equal to the known net height of the first deposition or may be set to slightly more than that height so as to ensure that the etching depth reaches material associated with any material deposited in association with formation of a previously formed layer. Upon completion of this etching operation, the contact mask or adhered mask is removed. The process next moves on to a blanket deposition operation 208 that deposits a second material (by electroplating) onto the substrate including into the void formed by the etching operation 206 and onto the previously deposited material. In some alternative embodiments, the mask (e.g. contact mask or adhered mask of the open volume type) used to perform the etching operation 206 may remain in place during the depositions operation such that a more selective deposition occurs.

[0111] After depositing material to a desired depth (e.g. at or somewhat more than a depth of one layer thickness) the process proceeds to a planarization operation 210 that brings the two material layer to a desired height (e.g. the height of one layer thickness). By the operations 202 to 210 , the formation of a layer of the structure is completed.

[0112] Next the process proceeds to inquiry 212 where the question is posed as to whether there is another layer to form. If the answer is “no” the process proceeds to block 218 where the sacrificial material is removed (e.g. via chemical etching) and the desired three-dimensional structure is revealed. Of course in alternative embodiments other processing steps may be performed in addition to the removal operation. After the removal operation 218 , the process ends at block 220 . Of course in still other embodiments, the removal of the sacrificial material may not be required.

[0113] If the answer to the inquiry 212 is “yes” the process proceeds to inquiry 214 where the question is posed as to whether the process will follow the same basic operations 202 - 210 . To conclude that that the same basic operations will be followed, no changes more radical than changing of process parameters or the changing of the selective etching pattern (e.g. using mask with a different pattern) may be tolerated. If the answer to the inquiry is “yes” the process loops back to operation 202 . If the answer is “no”, the process proceeds to operation. 216 where an undefined set of operations occurs that results in the formation of the next layer. The undefined processes in operation 216 may include operations similar to those in 202 - 210 as well as various other operations and orders of operation (e.g. those found in other embodiments specifically set forth herein, those found in various EFAB embodiments set forth in one or more of the patents or publications incorporated herein by reference, or combinations of operations which are readily understood by those of skill in the art in view of the teaching set forth herein). After completion of the operation 216 the process loops back to inquiry 212 . Of course the process of FIG. 7 may include various other operations, such as cleaning and surface preparation operations (e.g. activations) prior to or after each of the operations 202 - 210 .

[0114] In some embodiments, various additional or supplemental operations will be added to the process, such as intermediate cleaning operations, activation operations, inspection or measurement operations, and the like.

[0115] FIG. 8 provides a simplified process for forming three-dimensional structures as compared to that provided for by the process of FIG. 7 . In this simplified process all layers are formed using the same set of operations with only the selective patterning of each layer changing as appropriate from layer to layer. Furthermore, the first planarization operation 204 that was called for in FIG. 7 is dropped as unnecessary. Like elements of FIGS. 7 and 8 are marked with like reference numerals.

[0116] FIGS. 9 ( a )- 9 ( j ) illustrate the application of the process of FIG. 7 to the formation of a particular structure. FIG. 9 ( a ) indicates that a substrate 222 is supplied on to which layers of material will be deposited.

[0117] FIG. 9 ( b ) illustrates occurrence of a blanket deposition of a first material 226 onto the substrate according to operation 202 . The deposition height is somewhat greater than the layer thickness and preferably somewhat greater than a desired interim planarized thickness for the layer.

[0118] FIG. 9 ( c ) shows the deposition of FIG. 9 ( b ) after it has been planed down (Operation 204 ) to a desired interim thickness equal to the layer thickness plus some desired incremental amount (LT+δ). The use of a layer that is somewhat thicker than the layer thickness (LT) helps ensure appropriate contact between like material or desired materials on successive layers.

[0119] FIG. 9 ( d ) shows that a contact mask 228 (e.g. a CC mask) has been placed against the previously deposited layer (i.e. a modified substrate which is the original substrate plus the deposited material) and that etching operation 206 has been initiated to selective remove material and create voids 234 ′ in the previously deposited material 226 .

[0120] FIG. 9 ( e ) depicts the result of the completed etching operation 206 . The voids 234 ′ have grown into voids 234 having a depth equal to (LT+δ). Of course, in other embodiments the depth of etching may be different from that used in this example. In other embodiments the depth of etching may be somewhat greater than the believed deposit thickness to help ensure appropriate contact between like or desired materials on successive layers.

[0121] FIG. 9 ( f ) depicts the blanket deposition of a second material 238 on to the first material 226 and into the voids 234 according to operation 208 . In this embodiment the depth of deposition is at least as great as the layer thickness (LT).

[0122] FIG. 9 ( g ) depicts the resulting and finalized first layer 251 composed of regions of the first material 226 and regions of the second material 238 after a planarization operation 210 that sets the height of the layer to LT.

[0123] FIG. 9 ( h ) depicts a side view of the set of layers for a completed structure. Each layer is formed by repetition of the operations 202 - 210 . Depending on which of the two materials is the structural material and which is the sacrificial material, after a material selective etching operation 218 , the multi-layer three-dimensional structure is revealed as that shown in FIG. 9 ( i ) where the structural material is the second material 238 and the sacrificial material was the first material 226 or as that shown in FIG. 9 ( j ) where the structural material is the first material 226 and the sacrificial material was the second material 238 .

[0124] In some alternative embodiments, if material 226 is the structural material, the formation of the last layer may have ended with the etching of material 226 since the deposition of material 238 on the final layer may not be necessary. In some alternative embodiments the order of deposition of the two materials may be selected (e.g. reversed between selected layers) so that selected geometric features of structural material may be obtained (e.g. if the etching operation produces a lateral expansion of the etched regions as vertical etching occurs, an outward taper of the structural material may be obtainable by etching into the sacrificial material or alternatively, an inward taper of the structural material may be obtainable by etching into the structural material).

[0125] FIG. 10 depicts a process flowchart for a preferred three material embodiment. Many elements of FIG. 10 are similar to the elements of FIG. 7 and like operations are designated with like numerals. The process starts off similar to that of FIG. 7 with operations 202 - 210 . The only difference potentially being in the two levels of planarization. Operation 204 may set the planarization level at LT+δ or at LT+2*δ or the like. Since there will be three planarization operations during the formation of the layer, it may be desirable to have each one trim down the layer slightly or it may be acceptable to have all planarization operations set the level at LT+δ with the exception of the last one which will set the level at LT. Operation 210 may set the planarization at a desired level (e.g. LT+δ, LT, or something equal to or less than the planarization level set by 204 and something greater than or equal to the planarization level that will be set by operation 266 .

[0126] Operation 210 is followed by a selective etching 262 which is performed in preparation for a blanket deposition 264 of a third material that will fill the voids created by etching operation 262 . In some alternative embodiments, the blanket deposition of operation 264 may be replaced by a selective deposition operation that potentially uses the same mask as that use for the etching operation 262 .

[0127] Operation 264 blanket deposits a third material into the voids created by etching operation 262 as well as to other locations.

[0128] Operation 266 calls for the planarization of the deposited material and since it is the last planarization performed in completing the present layer, it sets that planarization level at LT.

[0129] Operation 266 completed the formation of a layer. Additional operations are used to determine when formation of the multilayer structure has been completed and if appropriate to determine how additional layers should be added. These additional operations are analogous in those set forth in FIG. 7 and are labeled with like reference numerals 212 - 220 . Operation 214 has been labeled Operation 214 ′ as layer formation process of FIG. 10 involves eight operations instead of five as was the case with the embodiment of FIG. 7 .

[0130] FIGS. 11 ( a )- 11 ( n ) illustrate the application of the process of FIG. 10 to the formation of a particular structure. FIG. 11 ( a ) indicates that a substrate 222 is supplied on to which layers of material will be deposited.

[0131] FIG. 11 ( b ) illustrates a blanket deposition of a first material 226 onto the substrate (which may contain previously formed layers that include one or more materials—not shown) according to operation 202 . The deposition height is somewhat greater than the layer thickness (LT) and preferably somewhat greater than a desired interim planarized thickness for the layer.

[0132] FIG. 11 ( c ) shows the deposition of FIG. 11 ( b ) after it has been planed down (operation 204 ) to a desired interim thickness equal to the layer thickness plus some desired incremental amount (LT+δ).

[0133] FIG. 11 ( d ) shows that a contact mask 228 has been placed against the previously deposited layer (i.e. a modified substrate which is the original substrate plus the deposited material) and that an etching operation 206 has been initiated to selectively remove material and create voids 234 ′ in the previously deposited material 226 . In some alternative embodiments an adhered mask may be used as opposed to the contact mask.

[0134] FIG. 11 ( e ) depicts the result of the completed etching operation 206 . The voids 234 ′ have grown into voids 234 having a depth equal to (LT+δ). In other embodiments the depth of etching may be different from that used in this example (e.g. somewhat greater than LT+δ to help ensure contact with material deposited in association the previous layer).

[0135] FIG. 11 ( f ) depicts the blanket deposition of a second material 238 on to the first material 226 and into the voids 234 according to operation 208 . In this embodiment the depth of deposition is at least as great as LT but more preferably at least as great as LT+δ. In some alternative embodiments, the blanket deposition of operation 208 may be replaced by a selective deposition operation that may use the mask that patterned the selective etching operation particularly when that mask is of the open volume type.

[0136] FIG. 11 ( g ) depicts interim layer containing the first and second materials and having a thickness of LT+δ. This layer level and height is set by planarization operation 210 .

[0137] FIG. 11 ( h ) shows that a contact mask 272 has been placed against the previously deposited layer (i.e. a modified substrate which is the original substrate plus the deposited material) and that an etching operation 262 has been initiated to selectively remove material and create voids 272 ′ in the previously deposited material 226 . FIG. 11 ( i ) depicts the result of the completed etching operation 262 . The voids 272 ′ have grown into voids 272 having a depth equal to (LT+δ). In other embodiments the depth of etching may be different from that used in this example (e.g. somewhat greater than LT+δ to help ensure contact with material deposited in association the previous layer). In other alternative embodiments, the pattern of deposition of material 238 may have been modified so that the etching of operation 262 may have cut into material 238 instead of 226 . In still other embodiments, the patterning of deposition of material 238 may have been modified so that the etching of operation 262 may have cut into a combination of materials 238 and 226 . FIG. 11 ( j ) depicts the blanket deposition 264 of a third material 274 on to the first material 226 and the second material 238 and into the voids 272 . In this embodiment the depth of deposition is at least as great as the layer thickness. In some alternative embodiments the blanket deposition may be replaced by a selective deposition or a partially selective deposition which could result in less wasted deposition of the third material. Such selective or partially selective deposition may be implemented in a variety of different ways including for example by using a mask.

[0138] FIG. 11 ( k ) depicts the resulting and finalized first layer 282 composed of regions of the first material 226 and regions of the second material 238 and regions of a third material 274 after a planarization operation 266 that sets the final layer level and the height of the layer to LT.

[0139] FIG. 11 ( l ) depicts a side view of the set of layers for a completed structure. Each layer is formed by repetition of the operations 202 - 210 and 262 - 266 . Depending on which of material or materials are the structural material or materials (i.e. 226 , 238 , 274 , 226 and 274 or 226 and 238 , or 238 and 274 ) and which material or materials are the sacrificial material or materials ( 238 and 274 , 226 and 274 , 226 and 238 , or 238 , 274 , or 226 ), after an etching operation 218 or operations (not shown), the multi-layer three-dimensional structure is revealed. An example of such a three-dimensional structure is shown in is shown in FIG. 11 ( m ) where the structural materials are the second material 238 and the third material 274 and the sacrificial material was the first material 226 . Another example is shown in FIG. 11 ( n ) where the structural materials are the first material 226 and the third material 228 and the sacrificial material was the second material 238 . In other some embodiments three-dimensional structures may be formed from single materials or other combinations of materials. In some other embodiments, operation 218 may be eliminated in its entirety if the structure is appropriately defined by the entirety of materials deposited during layer formation operations.

[0140] FIG. 12 depicts a process flowchart for a preferred three material embodiment where a portion of the selective patterning is performed using selective etching and a portion is performed using selective deposition. In this embodiment, operations 202 - 206 are replaced with a single selective deposition operation 302 , after which the process proceeds onward from operation 208 through operation 220 as described in association with FIG. 10 .

[0141] FIGS. 13 ( a )- 13 ( c ) depict a side views progressing through various stages of the selective deposition operation 302 of FIG. 12 . FIG. 13 ( a ) shows the substrate 222 onto which deposition will occur. FIG. 13 ( b ) depicts a contact mask 304 in contact with the substrate with selective deposition 302 in progress. FIG. 13 ( c ) depicts the resulting pattern of material after the selective deposition 302 has been completed. In some alternative embodiments, instead of using a contact mask, an adhered mask may be used, or selective deposition may occur in some other manner (e.g. by deposition from an ink-jet or array of inkjets or the like).

[0142] FIG. 14 depicts a generalized flowchart for an embodiment of some aspects of the i