| 摘要 |
PURPOSE: A method of forming a field oxide is to reduce a width of the field oxide, compared with that in a conventional PBL(Poly Buffered LOCOS) process, thereby securing wider active region. CONSTITUTION: A pad oxide(2), a polysilicon layer(3), a nitride layer(4) and a CVD oxide is deposited on a semiconductor substrate(1) in this order and a photoresist pattern is formed thereon to define a field region. The CVD oxide and the nitride layer is etched obliquely so that a lower part of the etched portion becomes narrow, to expose a predetermined portion of the polysilicon layer. The photoresist pattern is removed and then the CVD oxide is removed by a wet-etching process. After a field oxide(7) is formed using an oxidation process, the polysilicon layer and the pad oxide are etched off.
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