摘要 |
A method for making a semiconductor device includes forming a first mask pattern on a device layer, forming a second mask pattern on the first mask pattern, etching the device layer not covered by the first and second mask patterns to thereby form a first trench, trimming the first mask pattern to form an intermediate mask pattern, depositing a material layer to fill the first trench, polishing the material layer to expose a top surface of the intermediate mask pattern, removing the intermediate mask pattern to form an opening, etching the device layer through the opening to thereby form a second trench.
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