Alpha Metals, Inc.

Peter Thomas McGrath

Wolfgang Hetterich

A process for manufacturing a multi-layer circuit board comprises applying a layer of a photo-resist to the conducting surface of an inner-layer and fixing the resin composition in a pre-selected pattern for example by exposing to UV radiation which results in polymerization in the exposed areas. After removing the non-fixed areas by developing in an aqueous developing solution and etching in an etching solution, the fixed areas of resin composition remain in place on the inner-layer and are directly adhered to the neighboring insulating layer in an adhesion step. The preferred resin compositions according to the invention comprise a first photo-polymerizable resin component having an acid number from 15 to 75, a second epoxy resin component having unreacted epoxy groups, and a photoinitator, the ratio or first to second resin components being at least 1:1.

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Surrey, United Kingdom

Peter Thomas McGrath