| 摘要 |
PURPOSE: A method for flattening of semiconductor device and a forming method using the flattening method is provided to prevent exceeding etching and dishing phenomenon. CONSTITUTION: A gate isolating membrane(21) is formed as a heat oxidation film on a silicon substrate(20) defined as a cell area(c2). A doped polysilicon layer is stuck and a perry area(p2) and nitride(23) is evaporated. Operating photo etching process, a gate line(22) is made by patterning. On the cell area(c2), low density of a source/drain impurity spreading part is built by ion implantation and on the perry part(p2), high density of impurity spreading part is constructed. An oxidation layer(25) is adhered on the substrate(20). A photoresist is made only on the perry part(p2) and a gate side spacer(24) is moulded by operating etchback process on exposed cell area(c2). After making high-density ion implantation, the photoresist is removed. A doped polysilicon layer(26) is created using CVD(Chemical Vapor Deposition) method on the whole substrate(20) for forming contact plug. A supplementary layer(27) is added on the polysilicon layer(26). To obtain plain polysilicon layer(26), an CMP(Chemical Mechanical Polishing) process is executed. By enforcing etchback, a plug is completed in cell part(c2) and the whole part of oxidation layer(25) in perry part(p2) is exposed by erasing all of the polysilicon layer(26).
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