| US 7,507,617 B2 | ||
| Method for manufacturing semiconductor device | ||
| Hideto Ohnuma, Kanagawa (Japan); and Kouki Inoue, Kanagawa (Japan) | ||
| Assigned to Semiconductor Energy Laboratory Co., Ltd., Kanagawa-Ken (Japan) | ||
| Filed on Dec. 16, 2004, as Appl. No. 11/12,172. | ||
| Claims priority of application No. 2003-431369 (JP), filed on Dec. 25, 2003. | ||
| Prior Publication US 2006/0134891 A1, Jun. 22, 2006 | ||
| Int. Cl. H01L 21/84 (2006.01) | ||
| U.S. Cl. 438—166 [257/E21.561] | 28 Claims |
| 1. A method for manufacturing a semiconductor device comprising the steps of:
forming a first silicon oxide film over a first crystalline semiconductor film crystallized by using an element that promotes
crystallization, the first crystalline semiconductor film comprising silicon;
forming a second semiconductor film comprising amorphous silicon over the first silicon oxide film;
performing a heat treatment wherein a second silicon oxide film is formed on the second semiconductor film; and
removing the second silicon oxide film by using a solution containing fluorine and a substance having surface activity.
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