Method of forming a isolation in semiconductor device

摘要

A method for forming an isolation layer of a semiconductor device is provided to form an HDP(high density plasma) oxide layer with a minimized overhang by performing a deposition process, a wet etch process and a deposition process on a structure including a trench. A semiconductor substrate(100) including a trench(114) in an isolation region is prepared. A first insulation layer(118) is deposited on a structure including the trench to partially fill the trench. A second insulation layer(120) is formed on the first insulation layer to completely fill the trench. A polishing stop layer(124) and a third insulation layer(122) are formed on the second insulation layer. A planarization process for etching the third insulation layer is performed. A first etch process for removing the polishing stop layer is performed. A second etch process is performed to remove the second insulation layer. A fourth insulation layer(126) is formed on the first insulation layer to completely fill the trench. The process for forming the first insulation layer can include the following steps. A first HDP oxide layer is performed to partially fill the trench. A second HDP oxide layer is formed on the first HDP oxide layer to additionally and partially fill the trench.