Elimination of Fractures in Plated-Through-Hole Printed Circuit Boards by the Use of Ductile Plating

This paper describes a printed wiring board manufacturing process which assures a crack-free plated-through-hole. The continuity between layers of printed circuit boards is achieved by depositing electroless copper followed by electroplated copper in a hole drilled through the layers. It was found that conventional boards were subject to cracking at the barrel of these holes during soldering. The incipient cracking, due to the differential in coefficient of linear thermal expansion of the G-1O, epoxy-glass and the electrodeposited copper is eliminated by the use of a ductile layer of cyanide copper.