| 摘要 |
A method for manufacturing a semiconductor device is provided to reduce a moat between a cell part and a peripheral part, and an effective field oxide height of an effective element isolation region of an effective element and short of a recess gate by performing two step etching processes with different etching time. A pad oxide layer and a pad nitride layer are formed in an upper part of a semiconductor substrate(61). A trench defining an active region is formed by defining the pad nitride layer, the pad oxide layer, and the semiconductor substrate with a predetermined thickness. A sacrificial oxide layer is formed inside the trench. A side wall oxide layer(63) is formed inside the trench. The fluid dielectric(64) is deposited in the lower part of the trench. The fluid dielectric becomes highly dense by performing the thermal process. A gap fill oxide layer(65) is reclaimed in the front of the substrate including the fluid dielectric. A screen oxide layer, a mask oxide layer and a recess mask pattern are formed on the semiconductor substrate successively. The recess mask pattern, the mask oxide layer and the screen oxide layer are removed by performing the wet etch process. The dry etching process is performed to remove the mask oxide layer and the screen oxide layer of the peripheral part.
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