Advanced Solder Masks

Conventional screen printed two pack solder resists have served the industry well for many years, and will continue in their present form into the foreseeable future. However, with the introduction of newer printed circuit board technologies, such as PTH boards with 4 thou tracks and gaps, and less, hot air solder levelling and the use of SMD and VLSIs require a solder mask to be applied with definitions and specifications not easily achieved. Exciting developments in resin technology have opened new horizons in UV setting and photo‐imaging which allow the advantages of screen printing to be retained with considerable improvements in efficiency and definition. Photo‐imaging also opens up new ways of coating solder mask onto printed circuit boards and these will also be discussed with their implications on future trends. The introduction of these new solder masks and novel applications will be for specific areas in the market and these will be identified and coupled with predictions for market growth into the 1990s.