Fine Lines in High Yield (Part CV): Laser Direct Imaging Update

摘要

During the past year PWB fabricators have shown a renewed interest in LDI after about two years of relative dormancy. It appears that there are several drivers for this development. The growing need for: "true position" imaging of small features over large formats, improved layer-to-layer registration, the "scaling" of an image (i.e., changing the image dimensions and/or shifting the image for best-fit registration to a shifted or distorted reference image), and lower cost of ownership for an LDI system. These needs are now met through improved capabilities of the LDI imager, longer life and lower power consumption of solid state lasers, and advanced photoresists for primary imaging as well as soldermasks with reasonable photospeed. Evidence for the growing acceptance of LDI beyond quick-turn, small lot applications is Tyco's investment in multiple LDI imagers to enable them to process difficult jobs at reasonable yields.