Chartered Semiconductor Manufacturing Ltd (Corporation)

Vijai Komar Chhagan

Yelehanka Ramachandramurthy Pradeep

Mei Sheng Zhou

Simon Yew-Meng Chooi

Subhash Gupta

Henry Gerung

A method for forming an L-shaped spacer using disposable polysilicon top spacers. A semiconductor structure is provided having a gate structure thereon. A liner oxide layer is formed on the gate structure. A dielectric spacer layer is formed on the liner oxide layer. A disposable polysilicon top spacer layer is formed on the dielectric spacer layer. The disposable polysilicon top spacer layer is anisotropically etched to form disposable polysilicon top spacers. The dielectric spacer layer is etched to form L-shaped dielectric spacers, using the disposable polysilicon top spacers as an etch mask. The disposable polysilicon top spacers are removed leaving an L-shaped dielectric spacer. In one embodiment, lightly doped source and drain regions are formed prior to forming the liner oxide layer and the L-shaped spacers.

Method for forming an L-shaped spacer using a disposable polysilicon spacer

A method for forming an extended metal gate without poly wrap around effects. A semiconductor structure is provided having a gate structure thereon. The gate structure comprising a gate dielectric layer, a gate silicon layer, a doped silicon oxide layer, and a disposable gate layer stacked sequentially. Spacers are formed on the sidewalls of the gate structure. A dielectric gapfill layer is formed over the semiconductor structure and the gate structure and planarized, stopping on the disposable gate layer. A first silicon nitride layer is formed over the disposable gate layer, and a dielectric layer is formed over the first silicon nitride layer. The dielectric layer is patterned to form a trench over the gate structure; wherein the trench has a width greater than the width of the gate structure. The first silicon nitride layer in the bottom of the trench and the disposable gate layer are removed using one or more selective etching processes. The doped silicon oxide layer is removed using an etch with a high selectivity of doped silicon oxide to undoped silicon oxide. A barrier layer is formed over the gate silicon layer, and a metal gate layer is formed on the barrier layer; whereby the metal gate layer has a greater width than the gate structure.

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Belgrave, United Kingdom

Vijai Komar Chhagan