Patterson & Sheridan, LLP
LPCVD gate hard mask
A gate hard mask is deposited on a gate structure using low pressure chemical vapor deposition (LPCVD). By doing so, the wet etch removal ratio (WERR) of the gate hard mask relative to the underlying polysilicon gate layer is increased when compared to prior art hard masks. The LPCVD gate hard mask will not only etch faster than prior art hard masks, but it will also reduce undercutting of the gate oxide. To provide additional control of the wet etch rate, the LPCVD hard mask can be annealed. The annealing can be tailored to achieve the desired etching rate.
Applied Materials, Inc.
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Christopher Dennis Chorng-Ping Rajesh Hoiman
Bencher Chang Kanuri Hung