Masking substrates for application of protective coatings

Abstract

A method for applying a protective coating to selected portions of a substrate is disclosed. The method includes applying a mask to or forming a mask on at least one portion of the substrate that is not to be covered with the protective coating. The mask may be selectively formed by applying a flowable material to the substrate. Alternatively, the mask may be formed from a preformed film. With the mask in place, the protective coating may be applied to the substrate and the mask. A portion of the protective coating that overlies the mask may be delineated from other portions of the protective coating; for example, by cutting, weakening or removing material from the protective coating at locations at or adjacent to the perimeter of the mask. The portion of the protective coating that overlies the mask, and the mask, may then be removed from the substrate.

What is claimed: 
     
         1 . An electronic assembly comprising:
 an electronic assembly;   a mask over at least one selected portion of the electronic assembly, the mask conforming to a shape of the at least one selected portion;   a protective coating over at least some portions of the electronic assembly not covered by the mask.   
     
     
         2 . The electronic assembly of  claim 1 , wherein the mask comprises a hardened liquid mask material. 
     
     
         3 . The electronic assembly of  claim 2 , wherein the hardened liquid mask material comprises a hardened hot melt adhesive. 
     
     
         4 . The electronic assembly of  claim 2 , wherein the hardened liquid masking material comprises a hardened liquid solder mask material. 
     
     
         5 . The electronic assembly of  claim 1 , wherein the mask comprises at least one of a grease and a gel. 
     
     
         6 . The electronic assembly of  claim 1 , wherein the mask comprises a hardened liquid masking agent. 
     
     
         7 . The electronic assembly of  claim 1 , wherein the mask comprises a wrapper. 
     
     
         8 . The electronic assembly of  claim 7 , wherein the wrapper comprises a pre-formed, adhesive-coated polyethylene film. 
     
     
         9 . The electronic assembly of  claim 7 , further comprising:
 a hardened liquid mask material sealing peripheral edges of the wrapper.   
     
     
         10 . The electronic assembly of  claim 1 , wherein the protective coating comprises a moisture-resistant coating. 
     
     
         11 . The electronic assembly of  claim 10 , wherein the moisture-resistant coating comprises a poly(p-xylylene) coating. 
     
     
         12 . The electronic assembly of  claim 11 , wherein the poly(p-xylylene) coating comprises a substituted poly(p-xylylene) coating. 
     
     
         13 . The electronic assembly of  claim 10 , wherein the moisture-resistant coating comprises an aluminum oxide coating. 
     
     
         14 . The electronic assembly of  claim 1 , further comprising:
 at least one weakened region in the protective coating, around an outer periphery of the mask.   
     
     
         15 . The electronic assembly of  claim 1 , wherein the at least one weakened region comprises at least one of a cut, an elongated severed location, an elongated series of perforations and an elongated score. 
     
     
         16 . An electronic assembly comprising:
 an electronic assembly;   a mask over at least one selected portion of the electronic assembly, the mask comprising a wrapper conforming to a shape of the at least one selected portion; and   a sealant located around a perimeter of the at least one selected portion of the electronic assembly, the sealant providing a seal around a periphery of the wrapper.   
     
     
         17 . The electronic assembly of  claim 16 , wherein the sealant comprises an adhesive. 
     
     
         18 . The electronic assembly of  claim 16 , further comprising:
 another mask comprising a grease or a gel within at least one port, receptacle, opening or recess.   
     
     
         19 . A system for protectively coating a substrate, comprising:
 a masking component configured to apply a sealant around a periphery of at least one selected portion of a substrate and a preformed mask over the at least one selected portion of the substrate, the sealant sealing a periphery of the preformed mask around the periphery of the at least one selected portion of the substrate;   a coating component for applying a protective coating to at least a portion of the substrate, including the mask; and   a material removal component for removing a portion of the protective coating over the mask.   
     
     
         20 . The system of  claim 19 , wherein the masking component is further configured to cause the preformed mask to conform to a topography of the at least one selected portion of the substrate.