| 摘要 |
PURPOSE: A fabrication method of a semiconductor device is provided to improve polishing uniformity by decreasing the deposition thickness of a buried insulating layer at the center portion of a wafer. CONSTITUTION: After forming an insulating pattern(23) on a semiconductor substrate(21) defined by the center portion(I) and the edge portion(II), a photoresist pattern is formed so as to expose an isolation region. At this time, the insulating pattern(23) is stacked on sequentially a pad oxide and a pad nitride. A trench is formed by selectively etching the exposed substrate(21) using the photoresist pattern as a mask. At this time, the depth of the trench formed at the center portion(I) is shallower than that of the edge portion(II). A buried insulating layer(25) is formed in the trench so as to decrease the deposition thickness at the center portion(I) by controlling flow rate of SiH4 gas. By planarizing the buried insulating layer(25) using CMP, a trench isolation layer is formed.
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