Shallow trench isolation process

摘要

A shallow trench isolation (STI) process is described. A patterned mask layer is formed on a substrate, and then a trench is formed in the substrate with the mask layer as a mask. A portion of the mask layer around the trench is removed, and a portion of the substrate around the top portion of the trench is removed with the remaining mask layer as a mask. A liner layer is formed in the trench. The liner layer on the top portion of the trench is then removed with a pre-deposition process of an HDP-CVD process. Thereafter, an insulating material is filled into the trench, and the mask layer is removed with an etchant. In STI process, the liner layer comprises a material that can also be etched by the etchant.