Methods for forming semiconductor device

摘要

A method for forming a semiconductor device includes forming first and second hard mask layers overlying a semiconductor substrate and forming trenches through the second hard mask, the first hard mask, and into the substrate. A dielectric material is formed in the trenches to form shallow trench isolation regions, removing the second hard mask layer, and a floating gate material is formed overlying the first hard mask and the trenches. The method further includes repeating at least twice a process of forming a buffer layer over the floating gate material and using a polishing process to remove a portion of the buffer layer and a top portion of the floating gate material. Next, a dry etch process to remove a portion of the floating gate material above the shallow trench isolation regions and the remaining portions of the buffer layer to form floating gate structures.

主权项

1. A method for forming a semiconductor device, comprising:
forming a first hard mask layer overlying a semiconductor substrate; forming a second hard mask layer overlying the first hard mask layer; forming trenches through the second hard mask, the first hard mask, and into the substrate; forming a dielectric material in the trenches to form shallow trench isolation regions; removing the second hard mask layer; forming a floating gate material overlying the first hard mask and the trenches; repeating at least twice a process of forming a buffer layer over the floating gate material and using a polishing process to remove a portion of the buffer layer and a top portion of the floating gate material; using a dry etch process to remove a portion of the floating gate material above the shallow trench isolation regions and the remaining portions of the buffer layer to form floating gate structures.