Ultraprecision finishing technique by numerically controlled sacrificial oxidation

Abstract

Abstract A silicon-on-insulator (SOI) wafer is a semiconductor substrate used for high-performance devices. An ultrathin and extremely uniform SOI layer is required with the downsizing of devices. In this paper, numerically controlled sacrificial oxidation using localized atmospheric-pressure plasma was applied to the ultraprecision finishing of an SOI wafer. In a basic experiment, the relationship between the oxidation thickness profile and the dwell time was described. Surface roughness was also measured using an atomic force microscope. As a result of applying this finishing technique to a commercially available φ 300 mm SOI wafer, the standard deviation of the thickness of the top silicon layer was successfully improved from 0.415 to 0.127 nm.