| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a silicon carbide semiconductor device which includes a dry etching process which can trim a trench bottom part flat, without causing electric field concentration to form a rough having such acute angle as affects a breakdown strength characteristics, with a deep trench etching exceeding 10μm on an SiC semiconductor substrate becoming a practical process. SOLUTION: A first dry etching uses a mixed gas of SF<SB>6</SB>, O<SB>2</SB>, and Ar. In the mixed gas, Ar has the flow rate of 50-80%. Relating to the ratio of flow rates between SF<SB>6</SB>and O<SB>2</SB>, the flow rate of SF<SB>6</SB>is 50-70% of that of O<SB>2</SB>. The etching is made in the atmospheric pressure 0.5 Pa or less while the temperature of a silicon carbide semiconductor substrate is kept 70-100°C when etching. A second dry etching uses a mixed gas of Ar and O<SB>2</SB>. In the mixed gas, Ar has the flow rate of 50-80%, for oxygen plasma treatment. COPYRIGHT: (C)2009,JPO&INPIT
|
