Characterization of a low temperature, low pressure plasma enhanced chemical vapor deposition tetraethylorthosilicate oxide deposition process

Abstract

A low temperature (180 °C) and pressure (⩽750 mTorr) tetraethylorthosilicate (TEOS) oxide deposition process was developed and characterized in a commercially available plasma enhanced chemical vapor deposition reactor. The reactor uses a dual frequency, capacitively coupled, parallel plate electrode design, which employs multistation sequential deposition to enhance throughput and uniformity. Deposition rate, within wafer film thickness uniformity, and film stress were characterized as a function of process pressure, gas composition, rf power, and temperature. Production quality oxide films were deposited using low TEOS flow rate (45 sccm), high oxygen flow rate (4000 sccm), and low pressure (500 mTorr). Deposition rate increased linearly with TEOS flow rate and decreases with oxygen flow rate. Deposition rate was weakly dependent on high frequency power and independent of pressure in this low pressure regime. Film thickness uniformity across a 200 mm wafer improved with decreasing TEOS flow rate and pressure. Uniformity was a weak function of oxygen flow rate and high frequency power. Film stress became more compressive with decreasing TEOS flow rate and was a weak function of oxygen flow rate, high and low frequency power, and pressure. A high quality TEOS oxide was deposited in this new processing regime, suitable for integrated circuit applications.