Smooth, Anisotropic Etching of Indium Containing Multi-layer Structures Using a High Density ICP System
Yao-Sheng Lee, Mike DeVre, David Lishan, Brad Reelfs, Russ Westerman
Unaxis USA, Inc.
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In recent years, indium phosphide (InP) and other In-containing materials (e.g. InGaAs, InAlGaAsP) have extensively been used for fabrication of optoelectronic devices. To reduce the processing cost, high yield manufacturing processes are required for the volume production. In this paper, we present results for a production-worthy process producing an anisotropic, smooth and notch-free features using a high density Inductively Coupled Plasma (ICP) system. InP etching rates of up to 2.0 µm/min with selectivity to oxide or nitride hardmask materials of 30:1 are reported. An excellent uniformity over 4” wafer was achieved. In this study, an endpoint detecting system OES (optical emission spectroscopy) was also utilized to monitor the etching process.