Printed Board Assembly Cleanliness—Standards, Practice and Reliability Considerations

The transition to complex printed board assemblies in modern high technology equipment is described. These low voltage, densely packed PBAs with their decreasing insulation paths, manufactured for greatest speed with highly activated solder fluxes, demand both awareness and action to achieve the degree of cleanliness compatible with reliability requirements. This paper sets forth activities under way in Australia to define and adopt cleanliness Standards for use throughout the nation's manufacturing industry. It identifies and defines cleanliness and methods used to achieve and measure contamination that is introduced during PBA manufacture.