Thermal dissipating metal core printed circuit board

Abstract

A metal core printed circuit board which includes multiple layers of synthetic plastic resin material on a sheet of metal, and wherein the surface of the plastic material is of such character that it provides an acceptable bond on which are built up sundry layers of different metals, the innermost layer on the plastic surface and the other layers positioned one upon another, ultimately comprising a built up circuit pattern, and wherein areas intermediate the circuit pattern comprise an exposed surface of the resin material.

Having described the invention, what is claimed as new in support of Letters Patent is: 
     
       1. A metal core printed circuit board comprising a sheet of metal having a thickness slightly less than the thickness of a standard complete printed circuit board,   a base film of synthetic plastic resin forming a coating extending over at least one surface of said sheet, said coating having a roughened surface texture comprising a multiplicity of keying depressions,   a circuit pattern on said coating comprising conducting metallic lines,   said metallic lines comprising a base layer of nickel in keyed bonded engagement with said coating and the depresions therein, a film of copper in electroplated engagement with said nickel, an outer layer of nickel in electroplated engagement with said film of copper, a layer of pyrophosphate copper in bonded engagement with said last identified layer of nickel, and an overlying layer of metal unlike said copper and nickel in adhesive engagement with said pyrophosphate copper, there being spaces between said conducting metallic lines wherein said coating is exposed and said metal core is covered by said coating.   
     
     
       2. A metal core printed circuit board as in claim 1 wherein said base layer of nickel comprises a nickel deposit having initially applied portions in said keyed bonded relationship with the coating and other subsequently applied portions extending between said initially applied portions. 
     
     
       3. A metal core printed circuit board as in claim 1 wherein holes extend through the metal core and said coating extends throughout walls of said holes. 
     
     
       4. A metal core printed circuit board as in claim 3 wherein said holes communicate with said conducting metallic lines and portions of the material comprising said conducting metallic lines extend into the holes and are secured to the walls of said holes. 
     
     
       5. A metal core printed circuit board as in claim 1 wherein said coating and said circuit pattern is on both sides of said sheet. 
     
     
       6. A metal core printed circuit board as in claim 5 wherein holes through the sheet interconnect with the circuit pattern on both sides of the sheet and portions of the material comprising said conducting metallic lines extend through the holes and interconnect said lines. 
     
     
       7. A metal core printed circuit board as in claim 1 wherein said base film comprises a plurality of layers of successively applied films of heat cured polyurethane resin .[.separated by a primer.]. .Iadd.and wherein only the layer of resin nearest the metal is separated from the metal by a primer. .Iaddend. 
     
     
       8. A metal core printed circuit board as in claim 7 wherein there are not less than six layers of said resin.