Threaded Structures with Solder Control Features

Abstract

Threaded standoff structures may be provided with features that control the flow of solder. A base structure for a standoff may be formed from a solderphobic material such as brass. A through hole may be formed in the base structure. The base structure may be coated with a solderphilic material such as an inner layer of nickel and an outer layer of tin. A tapping tool may be used to remove the solderphilic material from the opening by tapping threads into the opening, thereby exposing the underlying base metal of the standoff in the opening. During attachment to a substrate such as a printed circuit board, the standoff may be exposed to molten solder. The solderphilic coating on the outer surface of the standoff may attract the molten solder, whereas the solderphobic base metal in the threaded opening may help prevent solder from contaminating the threads in the opening.

What is claimed is: 
     
         1 . A method for forming a threaded standoff comprising:
 with a machining tool, forming an opening in a base structure;   with a coating tool, coating a surface of the base structure with a solderphilic coating; and   with a tapping tool, forming threads in the opening while removing the solderphilic coating from the opening.   
     
     
         2 . The method defined in  claim 1  wherein the solderphilic coating comprises a material selected from the group consisting of: tin and nickel, and wherein removing the solderphilic coating from the opening comprises removing the material from the opening. 
     
     
         3 . The method defined in  claim 1  wherein the base structure comprises brass and wherein coating the surface of the base structure with the solderphilic coating comprises coating the brass with the solderphilic coating. 
     
     
         4 . The method defined in  claim 1  wherein the coating tool comprises a deposition tool, wherein the solderphilic coating comprises metal, and wherein coating the surface of the base structure with the solderphilic coating comprises depositing the metal on the surface of the base structure with the deposition tool. 
     
     
         5 . The method defined in  claim 1  wherein the coating tool comprises an electroplating tool, wherein the solderphilic coating comprises metal, and wherein coating the surface of the base structure with the solderphilic coating comprises electroplating the metal on the surface of the base structure with the electroplating tool. 
     
     
         6 . The method defined in  claim 1  wherein the base structure comprises brass and wherein removing the solderphilic coating from the opening comprises removing the solderphilic coating to expose the brass within the opening. 
     
     
         7 . The method defined in  claim 1  wherein the base structure is formed from a first material, wherein the solderphilic coating is formed from a second material, wherein the second material attracts solder more strongly than the first material, and wherein removing the solderphilic coating from the opening comprises removing the second material to expose the first material in the opening. 
     
     
         8 . A method for forming a threaded standoff comprising:
 forming an opening in a standoff member;   with a coating tool, coating a surface of the standoff member with a solderphilic coating; and   removing the solderphilic coating from the opening by forming threads in the opening with a tapping tool.   
     
     
         9 . The method defined in  claim 8  wherein the solderphilic coating comprises a material selected from the group consisting of: tin and nickel, and wherein coating the surface of the standoff member with the solderphilic coating comprises coating the surface of the standoff member with the material. 
     
     
         10 . The method defined in  claim 8  wherein the standoff member comprises brass and wherein removing the solderphilic coating from the opening comprises removing the solderphilic coating to expose the brass in the opening. 
     
     
         11 . The method defined in  claim 8  wherein the standoff member comprises an interior surface and an exterior surface, wherein the interior surface defines the opening, and wherein coating the surface of the standoff member with the solderphilic coating comprises coating the interior surface and the exterior surface with the solderphilic coating. 
     
     
         12 . The method defined in  claim 8  wherein forming the opening in the standoff member comprises drilling the opening in the standoff member with a machining tool. 
     
     
         13 . The method defined in  claim 8  wherein coating the surface of the standoff member with the solderphilic coating comprises coating the surface of the standoff member with the solderphilic coating after forming the opening in the standoff member. 
     
     
         14 . The method defined in  claim 8  wherein the coating tool comprises a deposition tool, wherein the solderphilic coating comprises metal, and wherein coating the surface of the standoff member with the solderphilic coating comprises depositing the metal on the surface of the standoff member using the deposition tool. 
     
     
         15 . The method defined in  claim 8  wherein the coating tool comprises an electroplating tool, wherein the solderphilic coating comprises metal, and wherein coating the surface of the standoff member with the solderphilic coating comprises electroplating the standoff member with the metal using the electroplating tool. 
     
     
         16 . The method defined in  claim 8  wherein the standoff member is formed from a first material, wherein the solderphilic coating is formed from a second material, wherein the first material repels solder more strongly than the second material, and wherein removing the solderphilic coating from the opening comprises removing the second material to expose the first material in the opening. 
     
     
         17 . A method for forming a threaded standoff that has a solderphilic surface that is configured to receive solder when attaching the threaded standoff to a solder pad and that has a threaded opening that is configured to receive a screw, the method comprising:
 forming an opening in a metal standoff member;   forming the solderphilic surface by coating the metal standoff member with a solderphilic coating; and   removing the solderphilic coating within the opening to expose underlying metal of the metal standoff member by tapping threads into the metal standoff member in the opening.   
     
     
         18 . The method defined in  17  wherein the underlying metal comprises a solderphobic material and wherein removing the solderphilic coating within the opening comprises removing the solderphilic coating to expose the solderphobic material in the opening. 
     
     
         19 . The method defined in  claim 17  wherein the solderphilic coating comprises an inner layer of nickel and an outer layer of tin and wherein forming the solderphilic surface comprises coating the metal standoff member with the inner layer of nickel and the outer layer of tin. 
     
     
         20 . The method defined in  claim 17  wherein forming the opening in the metal standoff member comprises machining the opening in the metal standoff member with a machining tool before forming the solderphilic surface.