Impregnation of Metal Complexes into Polymer Using Supercritical Fluid to Improve Adhesion Property of the Copper Plating - LPC Printed Circuit Boards

To preparing the printed circuit boards (PCB's) much more high speed processes are required keeping high quality of electrical properties. High reliability and guaranteed quality are also important. The latest PCB's are shifting into more fine line circuitry, high density and narrow space conductor lines. Recently, PCB's materials change from epoxy type to liquid crystalline polymer (LCP) type. An essential subject for this technology is to improve the weak copper adhesive peel strength on LCP insulation materials. To get the good adhesion property of copper plating, it is now widely applying Pd colloid solution method. To achieve more excellent adhesion for next decade generation PCB's, we are investigating supercritical fluid (SCF) method. In this paper, an attempt has been done to impregnate some metal complexes into LCP material and decomposed them to produce free metal in the resin by reduction. Using the deposited metal an efficient electro-less Cu plating is achieved. We will discuss on the selection of the metal complexes and impregnation condition of the complexes as well as peel strength of the plating.