MANUFACTURE OF PRINTED CIRCUIT SUBSTRATE

摘要

A substrate for printed circuitry to which surface mountable components may be attached is formed by the successive steps of forming a laminate consisting of a layer of an alloy (50) (such as an alloy consisting of 42% nickel and 58% iron) having a low coefficient of thermal expansion sandwiched between layers (40) of aluminium, heat treating the laminate to cause aluminium to diffuse into the alloy layer and annealing the laminate.