Patent ID: 7199053

Claim:
A method for detecting an end-point of a CMP process of a semiconductor device, comprising the steps of: sequentially forming a polysilicon film, a conductive layer, a hard mask nitride film on a semiconductor substrate; forming a buffer layer containing nitrogen on the hard mask nitride film; selectively etching the buffer layer, the hard mask nitride film, the conductive layer and the polysilicon film to form a gate line including a stacked structure of a polysilicon film pattern, a conductive layer pattern, a hard mask nitride film pattern and a buffer layer pattern; forming a spacer at a sidewall of the gate line; forming an interlayer insulating film on the semiconductor substrate including the gate line and the spacer; and subjecting the insulating film and the buffer layer of a CMP process using the hard mask nitride film pattern as an etching barrier film, wherein a concentration of NO gas generated upon exposure of the buffer layer in the CMP process is measured so as to detect an end-point of the CMP process.