Multi-step release method for electrochemically fabricated structures

Abstract

Multi-layer structures 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.

1 . An electrochemical fabrication process for producing a multi-layer three-dimensional structure from a plurality of adhered layers, the process comprising: 
 (A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein the depositing of at least one of the materials comprises an electrodeposition or electroless deposition operation;    (B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;    (C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate; and    (D) performing a second etching operation, which is distinct from the first etching operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.    
     
     
         2 . An electrochemical fabrication process for producing a multi-layer three-dimensional structure from a plurality of adhered layers, the process comprising: 
 (A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein at least one of the materials comprises a metal or electroless deposition operation;    (B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;    (C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate; and    (D) performing a second etching operation, which is distinct from the first etching operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.    
     
     
         3 . The process of  claim 1  additionally comprising: 
 (D) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;    wherein at least a plurality of the selective depositing operations comprise: 
 (1) contacting the substrate and the dielectric material of a selected preformed mask;  
 (2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and  
 (3) separating the selected preformed mask from the substrate.  
   
     
     
         4 . The process of  claim 1  wherein a plurality of selective depositing operations comprise: 
 (1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;    (2) in presence of a plating solution, conducting an electric current through the at least one opening in the adhered mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and    (3) removing the mask from the substrate.    
     
     
         5 . The process of  claim 1  wherein a plurality of selective depositing operations comprise: 
 (1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;    (2) while the patterned mask is adhered to the substrate, depositing a selected deposition material through the at least one opening in the adhered mask onto the substrate, and    (3) removing the mask from the substrate.    
     
     
         6 . The process of  claim 1  wherein the first etching operation comprises use of at least a first etchant and a first set of etching parameters and wherein the second etching operation comprises use of at least a second etchant and a second set of etching parameters.  
     
     
         7 . The process of  claim 6  wherein the first and second etchants are different from one another.  
     
     
         8 . The process of  claim 7  wherein the first etchant selectively attacks one of the materials of the layers while substantially non-reactive with regard to another material of the layers.  
     
     
         9 . The process of  claim 6  wherein the first set of etching parameters are different from the second set of etching parameters.  
     
     
         10 . The process of  claim 6  wherein the first and second etching operations are separated by an intervening operation.  
     
     
         11 . The process of  claim 1  where the first etching operation removes a first material and the second operation removes a second material which is different from the first material.  
     
     
         12 . The process of  claim 1  wherein the first etching operation ends at a hard stop.  
     
     
         13 . The process of  claim 1  where the three-dimensional structure is protected from the first etchant and etching operation by a material that substantially surrounds the structure and, which is not attacked significantly by the first etchant.  
     
     
         14 . The process of  claim 1  where the three-dimensional structure is protected from the first etchant and etching operation by a barrier material and by a substrate on which the structure is formed which are resistant to the first etching operation.  
     
     
         15 . The process of  claim 1  where the three dimensional structures is protected from the first etchant and etching operation by a barrier material which has a surface which is at least partially conformal with end spaced from a surface of the structure.  
     
     
         16 . An electrochemical fabrication process for producing a three-dimensional structure from a plurality of adhered layers, the process comprising: 
 (A) forming a layer by depositing at least one sacrificial material and at least one structural material onto a substrate, wherein the substrate may comprise previously deposited layers, and wherein the depositing of at least one of the materials comprises an electrodeposition operation or electroless deposition;    (B) repeating (A) one or more times such that a plurality of layers are formed and such that successive layers are formed adjacent to and adhered to previously formed layers;    (C) performing a first etching operation to remove at least a first portion of at least one material from the plurality of layers or from the substrate;    (D) performing an intervening operation, after performing the first etching operation;    (E) performing a second etching operation, after the intervening operation, to remove at least a portion of at least one material from the plurality of layers or from the substrate.    
     
     
         17 . The process of  claim 16  additionally comprising: 
 (F) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;    wherein at least a plurality of selective depositing operations comprise: 
 (1) contacting the substrate and the dielectric material of a selected preformed mask;  
 (2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and  
 (3) separating the selected preformed mask from the substrate.  
   
     
     
         18 . The process of  claim 16  wherein a plurality of selective depositing operations comprise: 
 (1) providing an adhered patterned mask on a surface of the substrate, wherein the mask includes at least one opening;    (2) in presence of a plating solution, conducting an electric current through the at least one opening in the adhered mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and    (3) removing the mask from the substrate.    
     
     
         19 . The process of  claim 12  additionally comprising: 
 (D) supplying a plurality of preformed masks, wherein each mask comprises a patterned dielectric material that includes at least one opening through which deposition can take place during the formation of at least a portion of a layer, and wherein each mask comprises a support structure that supports the patterned dielectric material;    wherein at least a plurality of the selective depositing operations comprise: 
 (1) contacting the substrate and the dielectric material of a selected preformed mask;  
 (2) in presence of a plating solution, conducting an electric current through the at least one opening in the selected mask between an anode and the substrate, whereby a selected deposition material is deposited onto the substrate to form at least a portion of a layer; and  
 (3) separating the selected preformed mask from the substrate.  
   
     
     
         20 . The process of  claim 18  wherein the first etching operation comprises use of at least a first etchant and a first set of etching parameters and wherein the second etching operation comprises use of at least a second etchant and a second set of etching parameters.  
     
     
         21 . The process of  claim 20  wherein the first and second etchants are different from one another.  
     
     
         22 . The process of  claim 21  wherein the first etchant selectively attacks one of the materials of the layers while substantially non-reactive with regard to another material of the layers.  
     
     
         23 . The process of  claim 22  wherein the at least one structural material comprises nickel, the at least one sacrificial material comprises copper, and wherein the first etchant is substantially selective to copper while substantially non-reactive with nickel.  
     
     
         24 . The process of  claim 16  wherein the intervening operation is an operation that removes etchant from at least one surface that was being etched by the first etching operation.  
     
     
         25 . The process of  claim 24  wherein the second etching operation uses the same etchant as did the first operation and wherein the second etching operation continues to operate on at least a portion of the at least one surface being etched by the first etching operation.  
     
     
         26 . The process of  claim 25  wherein the process additionally comprises: at least a second intervening operation which is performed after the second etching operation; and at least a third etching operation that is performed after the second intervening operation.  
     
     
         27 . The process of  claim 16  wherein the intervening operation removes an etching barrier that was protecting at least a portion of the multi-layer structure or substrate during the first etching operation.  
     
     
         28 . The process of  claim 27  wherein the second etching operation operates to remove material located around a previously protected surface.  
     
     
         29 . The process of  claim 27  wherein removal of the etching barrier occurs at least in part by use of a planarization operation.  
     
     
         30 . The process of  claim 28  wherein the first etching operation removes at least portion of a sacrificial material located in a passage or indentation on or within the substrate while the etching barrier protects at least a portion of the multi-layer structure.  
     
     
         31 . The process of  claim 30  wherein the second etching operation attacks sacrificial material forming part of the plurality of layers.  
     
     
         32 . The process of  claim 16  wherein the formation of the plurality of layers comprises formation of a desired structure and at least one temporary etching barrier that is adhered to the substrate or to structural material on at least one layer.  
     
     
         33 . The process of  claim 16  wherein the formation of the plurality of layers comprises formation of a desired structure and at least one temporary etching barrier that is adhered only to sacrificial material.  
     
     
         34 . The process of  claim 33  wherein the temporary barrier falls away from the desired structure after a surrounding quantity of sacrificial material has been removed.  
     
     
         35 . The process of  claim 16  wherein the intervening operation includes reorienting the structure with respect to a direction of application of an etchant or with respect to a gravitational force.