Patent ID: 9633858
Date: 2017-04-25
CPC Classifications: H01L

Claim:
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.