New High‐resolution Dry Film Photoresist

A new family of high resolution laminar dry films has been developed for making the next generation of high density printed circuit boards. Resolution below 50 micron lines and spaces can be obtained on a production basis with these high resolution films using a mild surface preparation and a collimated light source. Using specialised equipment and processes, patterns have been etched and plated which have resolved 18‐micron (075 mil) lines and spaces. Exposure and development latitudes, although tighter than for normal dry films, are still sufficient for standard shop operations.