| 摘要 |
PURPOSE: A method for forming a bit line contact hole of a semiconductor memory device is provided to prevent surface roughness of interlayer oxide between cell and periphery regions and thereby to prevent an insufficient removal of a polysilicon layer in the subsequent polishing step. CONSTITUTION: A word line(21), a nitride mask(22) and a nitride spacer(23) are formed on a silicon substrate(20), and an interlayer oxide(24) is formed thereon. The interlayer oxide(24) is then selectively etched through the first photoresist layer to form bit line contact holes exposing the substrate(20). Here, the nitride mask(22) in a periphery region(A) is exposed through the contact holes. Next, the first photoresist layer is removed and the second photoresist layer(PR2) is formed to fill the contact hole in the cell region(B). By the subsequent blanket etching or polishing, the second photoresist layer(PR2) is confined within the inside of the contact hole. Then, the nitride mask(22) in a periphery region(A) is etched for exposing the underlying word line(21). Here, since the interlayer oxide(24) is entirely exposed in both cell and periphery regions(A,B), surface roughness of the interlayer oxide(24) is prevented.
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