| 摘要 |
PURPOSE: A method for manufacturing an isolation layer of a semiconductor device is provided to improve yield and reliability of devices by forming the isolation layer using two-step CMP(Chemical Mechanical Polishing) processes. CONSTITUTION: A pad oxide pattern(22) and a nitride pattern(24) are sequentially formed on a substrate(20). A trench is formed in the substrate. An HDP(High Density Plasma) oxide layer(28) is filled in the trench. A CMP buffer layer is formed on the HDP oxide layer. By polishing selectively the buffer layer with high step using first CMP process, the HDP-oxide layer with high step is exposed. The exposed HDP-oxide layer is removed by wet or dry etching. Then, the buffer layer and the HDP-oxide layer are planarized to expose the nitride pattern by second CMP process.
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