| 摘要 |
PURPOSE:To secure good wiring resistance of a gate electrode giving no damage due to anisotropic etching for removal to an electrode part by thinly leaving an oxide film on the gate electrode part when removing the oxide film for forming an LLD (Lightly Doped Drain). CONSTITUTION:When anisotropic etching-back is performed after forming an oxide film all over the surface, the flat part and the step side part are etched differently from each other so that the oxide film 9b remains sufficient for an LDD mask. At the time, the oxide film 9a on the remaining high melting point metal silicide and the oxide film 9c on the flat part have the same thickness and this film thickness shall be such a degree as to not interfere implantation at the time of implanting impurities of high concentration. When ion implantation of high concentration impurities is performed, the part under the oxide film 9b of the low concentration impurity region 6 is not affected by this ion implantation so as to hold low concentration, while the other part undergoes implantation and heat treatment for forming a high concentration impurity region 8 having LDD structure. Thereby, the high melting point metal silicide surface at the time of etching is protected from damage thus to guarantee good wiring resistance of a gate electrode undergoing no influence of heat treatment of an after-process.
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