This Small Business Innovation Research Phase I project proposes a novel liquid photoresist chemistry to produce printed circuit boards (PCBs). This chemistry permits 100% solids application, eliminating objectionable solvents used in the application of currently available photoresists. The innovative chemistry uses a hardener blocked with a reactive component. This hardener is combined with suitable monomers, oligomers containing acid (COOH) functionality, polymeric binders, photoinitiators and photosensitizers. Following coating the material is heated to dissociate the blocked hardener, resulting in a partial cross linking of the reactive component, forming a tack-free (B-Stage) surface. The coating is patternable with U.V. light which through a free radical photoreaction results in selective polymerization of the coating. The unexposed material is developed with a 18 sodium or potassium carbonate water solution. The patterned photoresist is then used to define the negative image for subsequent etching, plating and electroplating. The photoresist is subsequently removed by stripping in a 108 sodium or potassium carbonate water solution. This program will demonstrate the feasibility of this approach by demonstrating this material on real circuit board substrate at a commercial printed circuit board vendor.
