APPARATUS AND METHOD OF MANUFACTURING METAL GATE SEMICONDUCTOR DEVICE

A method of manufacturing a semiconductor device includes providing a semiconductor substrate and forming a structure over the semiconductor substrate. The structure includes a sacrificial dielectric on the semiconductor substrate and a dummy gate over the sacrificial dielectric. The method further includes removing the dummy gate and the sacrificial dielectric from the structure thereby forming a trench. The method further includes filling a metal layer into the trench and covering over a top surface of an inter layer dielectric (ILD). The method also includes performing a chemical mechanical polishing (CMP) to expose the top surface of the ILD and heating the top surface of the ILD. Moreover, the method includes forming an etch stop layer on the top surface of the ILD.