Electron cyclotron resonance plasma etching of InP through-wafer connections at > 4 mu m/min using Cl-2/Ar

We report the development of very high etch rates (>4 mu m/min), for InP vi a hole processes. These processes were developed in an electron cyclotron r esonance system using a Cl-2/Ar plasma without heating the sample. The InP etch rates increased as a function of Cl-2 percentage in the Cl-2/Ar mixtur e, rf power, or microwave power. Via holes, with depths of 100 mu m, suitab le for monolithic microwave- integrated circuits applications, have been ac hieved at etch rates as high as 4 mu m/min. To the best of our knowledge, t his is the highest etch rate ever reported in InP for via hole applications . (C) 2000 American Vacuum Society. [S0734-211X(00)06304-6].