摘要 |
A method for forming a shallow-trench isolation starts with forming a polysilicon layer, which has less stress, as the mask layer for patterning the trench on a provided substrate. An oxide layer is then formed to cover the polysilicon layer and fill the trench. The oxide layer is then removed by first performing a chemical mechanical polishing process to remove a portion of the oxide layer, wherein the remains of the oxide layer still covers the polysilicon layer and fills the trench. After that, an etching back process is performed to remove the oxide layer from the top of the polysilicon layer to form the oxide plug, which is used as an isolation.
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