Characterization of a Time Multiplexed Inductively Coupled Plasma Etcher

We report the experimentally obtained response surfaces of silicon etching rate, aspect ratio dependent etching (ARDE), photoresist etching rate, and anisotropy parameter in a time multiplexed inductively coupled plasma etcher. The data were collected while varying eight etching variables. The relevance of electrode power, pressure, and gas flow rates is presented and has been found to agree with observations reported in the literature. The observed behavior presented in this report serves as a tool to locate and optimize operating conditions to etch high aspect ratio structures. The performance of this deep reactive ion etcher allows the tailoring of silicon etching rates in excess of 4 μm/min with anisotropic profiles, nonuniformities of less than 4% across the wafer, and ARDE control with a depth variation of less than 1 μm for trenches of dissimilar width. Furthermore it is possible to prescribe the slope of etched trenches from positive to reentrant. © 1999 The Electrochemical Society. All rights reserved.