| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve reduction in gate capacitance, prevention of occurrence of crystal defects, and improvement of gate breakdown voltage, in a method of manufacturing a trench-gate-type transistor. <P>SOLUTION: A trench 14 is formed on a surface of an N-type semiconductor layer 12. A silicon oxide film 15A is formed on the surface and in the trench 14 by thermal oxidation, and then a photoresist reinforcement film 16 covering the silicon oxide film 15A and a photoresist layer R2 covering the photoresist reinforcement film 16 are formed. Then, the photoresist layer R2 and the photoresist reinforcement film 16 are etched back to be left only in the trench 14. The silicon oxide film 15A at an upper side of a side wall of the trench 14 is removed by etching, using the photoresist layer R2 and the photoresist reinforcement film 16 as a mask. After removing the mask, a silicon oxide film 15B thinner than the silicon oxide film 15A is formed at the upper side of the side wall of the trench 14 by the thermal oxidation. After that, a gate electrode 18 is formed on the silicon oxide films 15A and 15B. <P>COPYRIGHT: (C)2012,JPO&INPIT |
