Taiwan Semiconductor Manufacturing Comp. Ltd.

Stan Chen

Jin-Dah Chen

Han-Wei Wu

Ming-Feng Shieh

Po-Chun Liu

Yu-Hsien Lin

A structure and a method of forming are provided. A first work function layer is formed over a first fin and terminates closer to the first fin than an adjacent second fin. A second work function layer is formed over the first work function layer and terminates closer to the second fin than the adjacent second fin. A third work function layer is formed over the first work function layer and the second fin. A conductive layer is formed over the third work function layer.

Gate formation with varying work function layers

First, second, and third trenches are formed in a layer over a substrate. The third trench is substantially wider than the first and second trenches. The first, second, and third trenches are partially filled with a first conductive material. A first anti-reflective material is coated over the first, second, and third trenches. The first anti-reflective material has a first surface topography variation. A first etch-back process is performed to partially remove the first anti-reflective material. Thereafter, a second anti-reflective material is coated over the first anti-reflective material. The second anti-reflective material has a second surface topography variation that is smaller than the first surface topography variation. A second etch-back process is performed to at least partially remove the second anti-reflective material in the first and second trenches. Thereafter, the first conductive material is partially removed in the first and second trenches.

Loading effect reduction through multiple coat-etch processes

A method includes forming a work function metal layer over first and second semiconductor fins extending upward from a substrate; forming a sacrificial layer straddling the first semiconductor fin but not overlapping the second semiconductor fin; patterning the first work function metal layer using the sacrificial layer, resulting in a patterned work function metal layer under the sacrificial layer, and a work function metal residue in the vicinity of the second semiconductor fin; selectively forming a protective layer on a side surface of the sacrificial layer and a side surface of the patterned first work function metal layer; removing the work function metal residue after selectively forming the protective layer; after removing the work function metal residue, removing the sacrificial layer and the protective layer; and forming a second work function metal layer over the first and second semiconductor fins.

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Taipei, Taiwan

Stan Chen