Hybrid STI gap-filling approach

摘要

A method of forming an integrated circuit structure includes providing a semiconductor substrate including a top surface; forming an opening extending from the top surface into the semiconductor substrate; and performing a first deposition step to fill a first dielectric material into the opening. The first dielectric material is then recessed. A second deposition step is performed to fill a remaining portion of the opening with a second dielectric material. The second dielectric material is denser than the first dielectric material. The second dielectric material is recessed until a top surface of the second dielectric material is lower than the top surface of the semiconductor substrate.