| 摘要 |
PROBLEM TO BE SOLVED: To prevent the variation of the thickness and electrical properties of a plurality of insulation film formed on the same semiconductor substrate. SOLUTION: An element isolation oxide film 3 and a first gate oxide film 5 are formed on a semiconductor substrate 1, the gate oxide film 5 in device forming regions 3b and 3c is removed using the mask of a silicon nitride film 7 formed on the first gate oxide film 5 of a device forming region 3a, and a second oxide film 11 is formed by thermal oxidation (D). A second nitride film 17 is formed, and a resist pattern 19 having an opening in the device forming region 3c is formed (E). The silicon nitride film 17 is removed using the mask of a resist pattern 19, the resist pattern 19 is removed, the gate oxide film 11 is removed using the mask of the silicon nitride film 17 (F), and a third gate oxide film is formed by thermal oxidation. Gate electrodes are formed on the first gate oxide film 5, on the second oxide film 11 and on the third oxide film after the silicon nitride film 7 and 17 are removed. COPYRIGHT: (C)2006,JPO&NCIPI
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