Method and structure for enabling controlled spacer RIE
First Claim
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1. A method of forming a semiconductor structure, said method comprising:
- providing a plurality of semiconductor fins extending upwards from a surface of a substrate, and a plurality of sacrificial spacer fins extending upwards from another surface of said substrate;
forming a sacrificial gate structure straddling over a portion of each semiconductor fin and each sacrificial spacer fin;
forming a dielectric spacer material surrounding said sacrificial gate structure, wherein said dielectric spacer material and each sacrificial spacer fin comprise a same dielectric material; and
performing a spacer reactive ion etch to said dielectric spacer material to provide a dielectric spacer on sidewall surfaces of said sacrificial gate structure, wherein during said spacer reactive ion etch exposed portions of each sacrificial spacer fin are removed, while maintaining a portion of each sacrificial spacer fin beneath said dielectric spacer and said sacrificial gate structure.
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Abstract
A method and structure to enable reliable dielectric spacer endpoint detection by utilizing a sacrificial spacer fin are provided. The sacrificial spacer fin that is employed has a same pitch as the pitch of each semiconductor fin and the same height as the dielectric spacers on the sidewalls of each semiconductor fin. Exposed portions of the sacrificial spacer fin are removed simultaneously during a dielectric spacer reactive ion etch (RIE). The presence of the sacrificial spacer fin improves the endpoint detection of the spacer RIE and increases the endpoint signal intensity.
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Citations
10 Claims
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1. A method of forming a semiconductor structure, said method comprising:
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providing a plurality of semiconductor fins extending upwards from a surface of a substrate, and a plurality of sacrificial spacer fins extending upwards from another surface of said substrate; forming a sacrificial gate structure straddling over a portion of each semiconductor fin and each sacrificial spacer fin; forming a dielectric spacer material surrounding said sacrificial gate structure, wherein said dielectric spacer material and each sacrificial spacer fin comprise a same dielectric material; and performing a spacer reactive ion etch to said dielectric spacer material to provide a dielectric spacer on sidewall surfaces of said sacrificial gate structure, wherein during said spacer reactive ion etch exposed portions of each sacrificial spacer fin are removed, while maintaining a portion of each sacrificial spacer fin beneath said dielectric spacer and said sacrificial gate structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification