Influence of Substrate Thickness and Preheat Treatment on the Adhesion and Dimensional Stability of Polyacrylate‐based Photoresist Lamination in Printed Circuit Fabrication

During fuser‐roll resist lamination processes, the copper‐clad FR‐4 substrate surface temperature was found to be inversely proportional to the substrate thickness. This temperature fluctuation has resulted in changes of adhesive forces in the copper/resist interface which in turn can affect the yield in the printed circuit manufacturing processes. By using infra‐red preheat treatment on the substrate prior to fuser‐roll lamination, the adhesion was found to be improved in the copper/resist interface. This adhesion improvement was found to be reflected in yield increase in fine line printed circuit fabrication.