METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE WITH RECESS GATE

摘要

A method for manufacturing a semiconductor device having a recess gate is provided to suppress the generation of a beak and to improve characteristics of the semiconductor device by rounding a top corner of a recess pattern. A sacrificial oxide layer(42) having a high wet-etch rate is formed on a semiconductor substrate(41). A hard mask pattern for recess is formed on the sacrificial oxide layer. The sacrificial oxide layer is wet-etched by using the hard mask pattern as an etch barrier. A recess(46) is formed by etching the semiconductor substrate. In the hard mask pattern forming process, a hard mask amorphous carbon layer and a hard mask SiON layer are formed on the sacrificial oxide layer. A photoresist pattern for defining a recess region is formed on the SiON layer. The SiON layer is etched by using the photoresist pattern as an etch barrier. The amorphous carbon layer is etched by using the photoresist pattern and the etched SiON layer as masks.