New Directions in Electrical Testing of PCBs for the 1990s Available to Purchase

As SMT circuit boards continue to increase in complexity, the PCB manufacturer—in order to stay alive in an increasingly competitive market—will be forced to produce boards of the highest quality to meet marketplace performance standards. In addition, he will have to produce them economically at a profit. The complex board of today will be a subsystem tomorrow. It will certainly contain finer features, more embedded resistors, and will even exhibit analogue‐like and RF‐like features plus even more sophisticated networks. All of these developments are expected to have a strong impact on electrical testing techniques. This paper discusses the problems of increasing yields by means of better process control and higher quality testing for a changing spectrum of faults. The effects of both latent and immediate PCB faults are examined for various grades of products, including low grade commercial, commercial, ground‐based military, high rel. commercial, and high tech. military and commercial. Illustrations and tables are provided showing the impact of fault detection on product quality as well as the economic impact achieved for various levels of product quality by means of software SPC (statistical process control). The most important issue facing the PCB manufacturer in the 1990s is certain to be quality of product. This paper outlines strategies for the manufacturer to improve his process through improving the quality of electrical test and the provision of highly accurate fault data as well as the highest possible fault coverage.