Method of planarizing substrate surface
A method of planarizing a substrate surface is disclosed. A substrate having a major surface of a material layer is provided. The major surface of the material layer comprises a first region with relatively low removal rate and a second region of relatively high removal rate. A photoresist pattern is formed on the material layer. The photoresist pattern masks the second region, while exposes at least a portion of the first region. At least a portion of the material layer not covered by the photoresist pattern is etched away. A polish stop layer is deposited on the material layer. A cap layer is deposited on the polish stop layer. A chemical mechanical polishing (CMP) process is performed to polish the cap layer.
1. A method of planarizing a substrate surface, comprising:
providing a substrate having a major surface of a material layer, wherein the major surface of the material layer comprises a first region with relatively low removal rate and a second region of relatively high removal rate;
depositing a polish stop layer on the major surface of the material layer;
forming a photoresist pattern on the polish stop layer, wherein the photoresist pattern masks the second region of relatively high removal rate, while exposes at least a portion of the first region with relatively low removal rate;
etching away at least a portion of the polish stop layer not covered by the photoresist pattern; and
removing the photoresist pattern.
2. The method according to claim 1 , wherein after removing the photoresist pattern, the method further comprises:
depositing a cap layer on the polish stop layer and on the material layer; and
performing a chemical mechanical polishing (CMP) process to polish the cap layer.
3. The method according to claim 2 , wherein the material layer comprises amorphous silicon.
4. The method according to claim 2 , wherein the CMP process stops on the polish stop layer.
5. The method according to claim 4 , wherein the polish stop layer comprises silicon nitride, and wherein the cap layer comprises silicon oxide or amorphous silicon.
6. The method according to claim 2 , wherein after performing the CMP process to polish the cap layer and the material layer, the method further comprises:
performing a dry etching process to etch the polishing stop layer and the material layer.