Support Layer for Thin Copper Foil

Abstract

A composite material useful for the manufacture of a circuit has a support layer, a metal foil layer having opposing first and second sides and a thickness of 15 microns or less and a release layer effective to facilitate separation of the metal foil layer from the support layer, the release layer disposed between and contacting both the support layer and the metal foil layer. A reactive element containing layer, which may be the support layer, effective to react with gaseous elements or compounds to form thermally stable compounds contacts the release layer. The composite material is preferably subjected to a low temperature heat treatment. The combination of the low temperature heat treatment and the reactive element containing layer results in reduced defects including blisters in the copper foil during subsequent processing.

1 .- 32 . (canceled) 
     
     
         33 . A composite material, comprising:
 a support layer containing a reactive element;   a metal foil layer having opposing first and second sides and a thickness of 15 microns or less;   a release layer effective to facilitate separation of said metal foil layer from said support layer, said release layer disposed between and contacting both said support layer and said metal foil layer.   
     
     
         34 . The composite material of  claim 33  wherein said reactive element is selected from the group consisting of titanium, zirconium, barium, magnesium, silicon, niobium, calcium and mixtures thereof. 
     
     
         35 . The composite material of  claim 34  wherein said reactive element is alloyed with said support layer. 
     
     
         36 . The composite material of  claim 35  having, by weight, from 0.001% to 50% of said reactive element. 
     
     
         37 . The composite material of  claim 36  wherein said support layer is a wrought, copper-base, material. 
     
     
         38 . The composite material of  claim 37  having, by weight, from 0.1% to 5% of said reactive element. 
     
     
         39 . The composite material of  claim 38  wherein said support layer is selected from the group consisting of copper alloys C199, C7025 and C654. 
     
     
         40 . The composite material of claim  5  wherein the wrought, copper-base, material has a yield strength in excess of 30 ksi following thermal exposure selected from the group consisting of 100° C.-350° C. for up to 48 hours.