Patent ID: 7081396

Claim:
A method for manufacturing device isolation film of semiconductor device, the method comprising the steps of: sequentially farming a pad oxide film and a pad nitride film on a semiconductor substrate; forming a trench by etching the pad nitride film, the pad oxide film and the semiconductor substrate; forming a liner nitride film on the entire surface; forming an oxide film for device isolation film filling the trench on the entire surface; polishing a predetermined thickness of the oxide film for device isolation film using a low selectivity slurry; polishing the oxide film for device isolation film using a high selectivity slurry to expose the liner nitride film; polishing the liner nitride film using a high selectivity slurry containing M x P y O z to expose the pad nitride film, where M is selected from a group consisting of an alkaline metal, an alkaline earth metal, a hydro alkaline metal, hydro alkaline earth metal, hydrogen and NH 4 + , where x, y and z are natural numbers in the range of 0 ≦x ≦3.1 ≦y ≦3 and2≦z≦5; and removing the pad nitride film.