| 摘要 |
PURPOSE:To restrain crystal defects from occurring in the corners of a trench so as to improve a semiconductor device in reliability by a method wherein the etching amount of the corners concerned, that is, the receding amount of a mask at the corners and the rounding amount of the corners are prescribed. CONSTITUTION:A first insulating layer 2, a second semiconductor substrate 3, and a second insulating layer 4 are formed on a first semiconductor substrate 1, the insulating layer 4 is patterned into a mask, the semiconductor substrate 3 is etched using the mask concerned to form a groove 5 so deep as to reach to the insulating layer 2. Then, the opening of the mask 4 is widened by etching and the insulating layer 2 exposed at the base of the groove 5 is etched to expose the upper the lower corners 6 and 7 of the semiconductor substrate 3 in contact with the groove 5, the corners 6 and 7 concerned are subjected to an isotropic etching technique to form an arc recess on each of the corners 6 and 7. When the opening of the mask 4 is widened by etching and the upper and the lower corners 6 and 7 of the semiconductor substrate 3 are subjected to an isoropic etching technique, the etching amount is prescribed. By this setup, crystal defects are restrained from occurring in the corners of a trench, so that a semiconductor device of this design can be improved in reliability.
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