METHOD FOR FABRICATING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a semiconductor device is provided to prevent polysilicon from being left without increasing etch time and etch quantity by blanket-etching a photoresist layer and a native oxide layer in a cell region and a peripheral circuit region and by etching a polysilicon layer in an unnecessary portion while reducing selectivity of the photoresist layer and the native oxide layer regarding polysilicon. CONSTITUTION: A semiconductor substrate having transistors and bitlines in the cell region and the peripheral circuit region is prepared. A nitride layer(100) and an oxide layer(110) for forming a capacitor are deposited on the bitline. After a capacitor formation portion is defined in the cell region, poly(120) for a lower electrode of capacitor is deposited on the resultant structure. After a photoresist layer(130) is deposited in the cell region, the poly for the lower electrode of capacitor in the peripheral circuit region is isotropically etched in a multilevel process using CF4 and O2 gas.