Evaluation of Permanent Solder Masks for High Reliability Applications

摘要

With more dense packaging of electronic subassembly printed wiring boards, it has become necessary for the military to fully understand materials and application problems of solder mask. This project was an attempt to experience and understand the problems associated with dry film and liquid permanent solder masks. Items such as registration, adherence, bubbles and voids, and environmental protection were examined. The result was a better understanding of each of these problems with conclusions that solder mask should be used only over bare copper circuitry and that liquid solder mask should not be used as an electrical insulating barrier.