| US 7,598,140 B2 | ||
| Method of producing a semiconductor device having an oxide film | ||
| Yuki Saito, Tokyo (Japan); and Yasutaka Kobayashi, Tokyo (Japan) | ||
| Assigned to Oki Semiconductor Co., Ltd., Tokyo (Japan) | ||
| Filed on Sep. 29, 2005, as Appl. No. 11/237,688. | ||
| Application 11/237688 is a division of application No. 10/336737, filed on Jan. 06, 2003, granted, now 6,979,858. | ||
| Prior Publication US 2006/0079078 A1, Apr. 13, 2006 | ||
| Int. Cl. H01L 21/336 (2006.01) | ||
| U.S. Cl. 438—265 [438/257; 438/261; 438/264; 438/593; 438/594; 438/595; 438/663; 438/770] | 11 Claims |
| 1. A producing method of a semiconductor device comprising:
forming a trapezoidal portion including a first oxide film which functions as a gate oxide film and a plurality of other films,
wherein said first oxide film has a first peripheral region including an end face of said first oxide film, and a first central
region surrounded by said first peripheral region; and
adjusting a thermal treatment of said trapezoidal portion so that a film thickness of said first oxide film in said first
peripheral region is thicker than a film thickness of said first oxide film in said first central region,
wherein a length from the end face to a midpoint of the first central region of said first oxide film of said trapezoidal
portion is L, and a length of said first peripheral region from the end face of said first oxide film is 2L/3.
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