HIGHLY ANISOTROPIC SELECTIVE REACTIVE ION ETCHING OF DEEP TRENCHES INSILICON

Reactive ion etching (RIE) of single crystal silicon using a gas mixtu re of SF6 and C2Cl3F3 in parallel plate electrode reactor was investig ated. A detailed study of etching characteristics as functions of gas composition, rf power, pressure, self-bias voltage was performed. The results were explored in order to optimize deep trench RIE process. Th e optimized process resulted in a high etch rate, a good selectivity s ilicon-to-photoresist, a high anisotropy, a nearly vertical etch profi le, and smooth surface morphology. This process was successfully used to fabricate silicon preforms for a replication technology of polymer- based devices.