Methods for forming semiconductor device
US9633858B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 2015 |
| Grant date | Apr 25, 2017 |
| Priority date | — |
| Expiry date | Sep 30, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/6894
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.