Patent ID: 7691738

Claim:
A method of fabricating a metal line in a semiconductor device comprising: forming a protective layer over a semiconductor substrate; and then forming a first contact plug in the protective layer; and then sequentially forming a first insulating interlayer and a first etch stop layer over the semiconductor substrate including the first contact plug; and then forming a trench by removing the first insulating interlayer and the first etch stopper layer to expose the first contact plug; and then forming a metal layer over the semiconductor substrate including the trench; and then simultaneously forming a metal line in the trench and a second contact plug extending from the metal line and projecting the trench by etching the metal layer; and then forming a second etch stop layer comprising silicon nitride directly contact the metal line and the second contact plug after simultaneously forming the metal line and the second contact plug; and then depositing a second insulating interlayer over the semiconductor substrate including the second contact plug; and then performing CMP until the second contact plug is exposed.