Method and structure for enabling high aspect ratio sacrificial gates
First Claim
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1. A method of forming a semiconductor structure comprising:
- forming a sacrificial gate stack over a surface of a substrate, wherein the sacrificial gate stack comprises a sacrificial gate material layer and a sacrificial gate cap layer;
providing a plurality of hard mask structures on a topmost surface of said sacrificial gate cap layer of said sacrificial gate stack;
forming an anchoring element straddling over at least one segment of each hard mask structure, wherein said anchoring element has sidewall surfaces that directly contact sidewall surfaces of each hard mask structure and a bottommost surface that directly contacts said topmost surface of said sacrificial gate cap layer;
patterning said sacrificial gate stack into a plurality of sacrificial gate structures and a pair of sacrificial gate cap anchoring portions utilizing said plurality of hard mask structures and said anchoring element as an etch mask, wherein each sacrificial gate structure comprises a sacrificial gate material portion and a sacrificial gate cap portion;
removing, after said patterning of said sacrificial gate structure, said anchoring element and each hard mask structure;
providing a spacer cavity by removing each sacrificial gate cap anchoring portion and remaining portions of said sacrificial gate material layer that are present beneath each sacrificial gate cap anchoring portion; and
filling said spacer cavity with a spacer dielectric material.
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Abstract
Sacrificial gate structures having an aspect ratio of greater than 5:1 are formed on a substrate. In some embodiments, each sacrificial gate structure straddles a portion of a semiconductor fin that is present on the substrate. An anchoring element is formed orthogonal to each sacrificial gate structure rendering the sacrificial gate structures mechanically stable. After formation of a planarization dielectric layer, each anchoring element can be removed and thereafter each sacrificial gate structure can be replaced with a functional gate structure.
105 Citations
15 Claims
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1. A method of forming a semiconductor structure comprising:
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forming a sacrificial gate stack over a surface of a substrate, wherein the sacrificial gate stack comprises a sacrificial gate material layer and a sacrificial gate cap layer; providing a plurality of hard mask structures on a topmost surface of said sacrificial gate cap layer of said sacrificial gate stack; forming an anchoring element straddling over at least one segment of each hard mask structure, wherein said anchoring element has sidewall surfaces that directly contact sidewall surfaces of each hard mask structure and a bottommost surface that directly contacts said topmost surface of said sacrificial gate cap layer; patterning said sacrificial gate stack into a plurality of sacrificial gate structures and a pair of sacrificial gate cap anchoring portions utilizing said plurality of hard mask structures and said anchoring element as an etch mask, wherein each sacrificial gate structure comprises a sacrificial gate material portion and a sacrificial gate cap portion; removing, after said patterning of said sacrificial gate structure, said anchoring element and each hard mask structure; providing a spacer cavity by removing each sacrificial gate cap anchoring portion and remaining portions of said sacrificial gate material layer that are present beneath each sacrificial gate cap anchoring portion; and filling said spacer cavity with a spacer dielectric material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification