Electroforming process

Abstract

Process of electroforming a metal structure, in particular a structure with a tip protruding from adjacent outer layers. The process comprises the following steps; a first layer is deposited on a substrate followed by one or more next layers partially overlapping the first layer to form an intermediate structure having a substrate surface facing the substrate; in a next step, the intermediate structure is removed from the substrate and one or more further layers are deposited on said substrate surface of the intermediate structure.

1 . A process of electroforming a metal structure, comprising steps of:
 depositing a first layer on a substrate and depositing one or more next layers partially overlapping the first layer to form an intermediate structure having a substrate surface facing the substrate; and   subsequently removing the intermediate structure from the substrate and depositing one or more further layers on said substrate surface of the intermediate structure.   
     
     
         2 . The process according to  claim 1 , further comprising forming a layer of a sacrificial material over the intermediate structure before said step of removing the intermediate structure from the substrate, and a final step of removing the layer of sacrificial material from the intermediate structure. 
     
     
         3 . The process according to  claim 2 , wherein the layer of sacrificial material is removed by selective etching. 
     
     
         4 . The process according to  claim 3 , wherein the sacrificial material is copper. 
     
     
         5 . The process according to  claim 1 , wherein the substrate is a mandrel with a pattern of a non-conductive coating defining an outline of at least the first layer. 
     
     
         6 . The process according to  claim 5 , wherein the first layer does not overgrow the non-conductive coating pattern. 
     
     
         7 . The process according to  claim 5 , wherein, before forming the one or more partially overlapping layers, the non-conductive coating is at least partially removed and a new non-conductive coating pattern is applied to confine the one or more partially overlapping layers. 
     
     
         8 . The process according to  claim 1 , wherein the first layer is of a different material than the one or more partially overlapping layers. 
     
     
         9 . The process of  claim 1 , wherein the first layer is rhodium or a rhodium alloy. 
     
     
         10 . The process of  claim 1 , wherein at least part of the one or more partially overlapping layers are of nickel or a nickel alloy. 
     
     
         11 . The process of  claim 5 , wherein the non-conductive coating pattern is a photoresist. 
     
     
         12 . The process according to  claim 5 , wherein the first layer does not overgrow the non-conductive coating pattern. 
     
     
         13 . The process according to  claim 6 , wherein, before forming the one or more partially overlapping layers, the non-conductive coating is at least partially removed and a new non-conductive coating pattern is applied to confine the one or more partially overlapping layers. 
     
     
         14 . The process according to  claim 11 , wherein, before forming the one or more partially overlapping layers, the non-conductive coating is at least partially removed and a new non-conductive coating pattern is applied to confine the one or more partially overlapping layers. 
     
     
         15 . The process according to  claim 12 , wherein, before forming the one or more partially overlapping layers, the non-conductive coating is at least partially removed and a new non-conductive coating pattern is applied to confine the one or more partially overlapping layers. 
     
     
         16 . The process according to  claim 2 , wherein the substrate is a mandrel with a pattern of a non-conductive coating defining an outline of at least the first layer. 
     
     
         17 . The process according to  claim 16 , wherein, before forming the one or more partially overlapping layers, the non-conductive coating is at least partially removed and a new non-conductive coating pattern is applied to confine the one or more partially overlapping layers. 
     
     
         18 . The process according to  claim 16 , wherein the first layer is of a different material than the one or more partially overlapping layers. 
     
     
         19 . The process of  claim 16 , wherein the first layer is rhodium or a rhodium alloy. 
     
     
         20 . The process of  claim 16 , wherein at least part of the one or more partially overlapping layers are of nickel or a nickel alloy.