| 摘要 |
PURPOSE: An isolation method of a semiconductor device is provided to be capable of preventing the recess generated at the upper edge portion of a trench and roundly forming the upper portion of the trench by thickly forming bird's beak shaped thermal oxide layer using a heat treatment. CONSTITUTION: After sequentially forming a pad oxide layer(202) and a silicon nitride layer(204) on a semiconductor substrate(200), a trench(210) is formed in the resultant structure. After depositing an HDP(High Density Plasma) oxide layer on the resultant structure, an insulating spacer(221) is formed by polishing the HDP oxide layer. A bird's beak shaped thermal oxide layer(211) is formed at the edge portion of the silicon nitride layer by carrying out a heat treatment. A gap-fill oxide layer(224) is formed in the trench.
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