A CHEMICALLY AMPLIFIED PHOTORESIST FOR VISIBLE LASER DIRECT IMAGING

Described in this study are the characteristics of a new photoresist designed specifically for laser direct imaging applications. This resist incorporates chemical amplification based on acid catalysis as a route to high sensitivity and uses a new and unique sensitizing dye to induce the formation of strong acid. The polymeric component of the resist is a methacrylate terpolymer with pendant reactive groups, which are cleaved by the action of acid. The resist is shown to meet all functional requirements for circuit board fabrication by visible laser direct imaging. Further, this resist is the first member of a family of related materials that offer the potential for very general application in packaging device fabrication. Described herein are examples of how this resist chemistry can be readily adapted for applications requiring near-UV or deep-UV sensitivity and how it can be extended to photoimageable solder-mask and to dry-film resist applications.