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

摘要

The present invention is directed to a method fordesmearing printed circuit boards using a plasma gasdesmearing medium produced between a pair of electrodes inan evacuated chamber wherein the material being desmearedis selected from the group consisting of epoxy andpolyimide. The method comprises desmearing with a plasmacomprising a gas mixture of 20-45% NF3 the remainder beingO2 wherein the chamber is evacuated to a pressure in therange of 1000 to 3000 milli-Torr, and wherein the powerdensity used to create the plasma is in the range of 0.08to 0.25 watt/cm2.