Determination of process margin and global planarization characteristics in the direct STI-CMP process

The direct shallow trench isolation-chemical mechanical polishing (STI-CMP) process without conventional reverse moat etch step was studied in order to compare the global planarization procedure in the each region with different pattern size. Because the removal rates of each region were different in the STI-CMP process, the determination of process margin is very important parameter in the viewpoint of exact control for polishing thickness. Therefore, the process margins (upper and lower limits), which can minimize the dishing effects in the large field area, were investigated through the analysis of global planarization. As a result, we could perfectly remove the silicon oxide on the silicon nitride layer in the moat region. This means that it was possible to achieve a global planarization without the complicated reverse moat process. (C) 2004 Kluwer Academic Publishers.