Method for forming image sensor
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChun-Wei Chia, Chun-Hao Chou, Kai-Chun Hsu, Kuo-Cheng Lee, Shyh-Fann Ting
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Abstract
A method includes depositing a gate dielectric layer over a substrate. A gate electrode layer, a protection oxide layer, and a hard mask are sequentially deposited over the gate dielectric layer. The gate electrode layer and the protection oxide layer are patterned by using the hard mask as an etching mask to form a gate structure over the gate dielectric layer. An etching process is performed to remove the hard mask and thin the protection oxide layer after forming the gate structure.
Claims20
A method comprising:
- depositing a gate dielectric layer over a substrate;
- sequentially depositing a gate electrode layer, a protection oxide layer, and a hard mask over the gate dielectric layer;
- patterning the gate electrode layer and the protection oxide layer by using the hard mask as an etching mask to form a gate structure over the gate dielectric layer;
- and
- performing an etching process to remove the hard mask and thin the protection oxide layer after forming the gate structure.
A method comprising:
- depositing a gate dielectric layer over a substrate;
- depositing a gate electrode layer over the gate dielectric layer;
- depositing a protection oxide layer over the gate electrode layer;
- depositing a hard mask over the protection oxide layer;
- pattering the gate dielectric layer, the gate electrode layer, the protection oxide layer, and the hard mask such that the gate dielectric layer comprises a first portion directly under the patterned gate electrode layer and a second portion spaced apart from the gate electrode layer, and the first portion is thicker than the second portion;
- and
- forming an oxide layer on a sidewall of the patterned gate electrode layer and in contact with a top surface of the first portion of the gate dielectric layer and a bottom surface of the protection oxide layer.
A method comprising:
- depositing a gate dielectric layer over a substrate;
- forming a gate structure over the gate dielectric layer, wherein the gate structure comprises:
- a gate electrode over the gate dielectric layer;
- a protection oxide layer over the gate electrode;
- and
- a hard mask over the protection oxide layer;
- forming a recess in the gate dielectric layer after forming the gate structure;
- and
- forming an oxide layer on a sidewall of the gate electrode, such that a first portion of the oxide layer is in contact with a portion of the gate dielectric layer and a second portion of the oxide layer overhangs above the recess of the gate dielectric layer, wherein forming the oxide layer is such that a top surface of the first portion of the oxide layer is in contact with the protection oxide layer.
Dependencies are inferred from the claim text.