Combined in-situ high density plasma enhanced chemical vapor deposition (HDPCVD) and chemical mechanical polishing (CMP) process to form an intermetal dielectric layer with a stopper layer embedded therein

摘要

A wafer planarization process which utilizes combined high density plasma chemical vapor deposition (HDP-CVD) process and chemical mechanical polishing (CMP) process is disclosed. This process includes the steps of (a) forming a first HDP-CVD layer on the surface of a semiconductor wafer using a first HDP-CVD composition having a higher etching/depositing component ratio and thus a lower CMP removal rate; (b) forming a second HDP-CVD layer on the first HDP-CVD layer using the same HDP-CVD process but with a second HDP-CVD composition having a highest etching/depositing component ratio and thus the lowest CMP removal rate; (c) forming a third HDP-CVD layer on the second HDP-CVD layer using the same HDP-CVD process but with a third HDP-CVD composition having a low etching/depositing component ratio and thus a high CMP removal rate; and (d) using a chemical mechanical process to remove at least a part of the third HDP-CVD layer using the second HDP- CVD layer as a stopper. All the three HDP-CVD compositions contain the same etching and silicon- containing deposition components so as to improve the CMP efficiency without incurring substantially increased fabrication cost.