DESMEAR AND ETCHBACK OF PRINTED CIRCUIT BOARDS USING AN NF_/O_ PLASMA GAS MIXTURE

摘要

The present invention is directed to a method for desmearing printed circuit boards using a plasma gas desmearing medium produced between a pair of electrodes in an evacuated chamber wherein the material being desmeared is selected from the group consisting of epoxy and polyimide. The method comprises desmearing with a plasma comprising a gas mixture of 20-45% NF3 the remainder being O2 wherein the chamber is evacuated to a pressure in the range of 1000 to 3000 milli-Torr, and wherein the power density used to create the plasma is in the range of 0.08 to 0.25 watt/cm2.