Taiwan Semiconductor Manufacturing Comp. Ltd.

Jung-Tzu Hsu

Jyh-Huei Chen

Yu-Hsien Lin

Ching-Chung Pai

A method of fabricating an integrated circuit device is provided. The method includes forming a replacement gate structure with a dummy polysilicon layer on a first surface of a substrate. The method further includes depositing a dielectric layer by a thermal process to form offset spacers on two opposing sides of the replacement gate structure, wherein the dielectric layer is deposited on the first surface and a second surface opposing the first surface of the substrate. The method further includes removing the dummy polysilicon layer from the replacement gate structure, wherein the dielectric layer on the second surface of the substrate protects the second surface of the substrate during the removing step.

Method of fabricating an integrated circuit device having backside bevel protection

The disclosure provides methods and structures for preventing exposing polysilicon layer and silicon substrate on the substrate backside to polysilicon etching chemistry during removal of the dummy polysilicon layer in replacement gate structures. A thermal deposition process or processes are used to deposit a dielectric layer for offset spacers and/or a contact etch stop layer (CESL) to cover the polysilicon layer on the substrate backside. Such mechanisms reduce or eliminate particles originated at bevel of substrate backside, due to complete removal of the polysilicon layer at the backside bevel and the resultant etching of silicon substrate.

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Taoyuan, Taiwan

Jung-Tzu Hsu