	US 11,658,230 B2
	Method for forming a semiconductor structure including plasma cleaning operations
Chun Hsiung Tsai, Hsinchu County (TW); Ru-Shang Hsiao, Hsinchu County (TW); and Clement Hsingjen Wann, Carmel, NY (US)
Assigned to Taiwan Semiconductor Manufacturing Company Ltd., Hsinchu (TW)
Filed by TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD., Hsinchu (TW)
Filed on Nov. 23, 2020, as Appl. No. 17/101,546.
Application 17/101,546 is a continuation of application No. 16/397,577, filed on Apr. 29, 2019, granted, now 10,847,636.
Claims priority of provisional application 62/724,898, filed on Aug. 30, 2018.
Prior Publication US 2021/0104619 A1, Apr. 8, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 29/66 (2006.01); H01L 21/306 (2006.01); H01L 21/02 (2006.01); H01L 21/3065 (2006.01); H01L 21/8234 (2006.01); H01L 29/78 (2006.01)

CPC H01L 29/66795 (2013.01) [H01L 21/0206 (2013.01); H01L 21/02057 (2013.01); H01L 21/02068 (2013.01); H01L 21/3065 (2013.01); H01L 21/30604 (2013.01); H01L 29/66545 (2013.01); H01L 29/785 (2013.01); H01L 21/823418 (2013.01); H01L 29/66636 (2013.01)]

20 Claims

1. A method for forming a semiconductor structure, comprising:

receiving a substrate, wherein a fin structure is formed on the substrate, and a dielectric layer is formed over the fin structure;

forming a sacrificial gate over the substrate, wherein a portion of the dielectric layer is exposed through the sacrificial gate;

forming recesses in the fin structure at two sides of the sacrificial gate; and

performing a cleaning operation with an HF-containing plasma, wherein the HF-containing plasma comprises HF and NH₃.

7. A method for forming a semiconductor structure, comprising:

receiving a substrate having a sacrificial semiconductor gate and a dielectric structure surrounding the sacrificial semiconductor gate;

removing a first portion of the sacrificial semiconductor gate to form a gate trench in the dielectric structure and to form a second portion of the sacrificial semiconductor gate in the gate trench by a first plasma, wherein residue is formed over the second portion; and

removing the residue from the second portion by a second plasma different from the first plasma, wherein the second plasma comprises a hydrogen plasma cleaning operation.

15. A method for forming a semiconductor structure, comprising:

receiving a substrate, wherein a fin structure is formed on the substrate, and a dielectric layer is formed over the fin structure;

forming a sacrificial gate over the substrate, wherein a portion of the dielectric layer is exposed through the sacrificial gate;

performing a first cleaning operation to remove the portion of the dielectric layer exposed through the sacrificial gate;

forming recesses in the fin structure at two sides of the sacrificial gate;

performing a second cleaning operation with an HF-containing plasma, wherein the HF-containing plasma comprises HF and NH₃;

forming a strained source/drain structure in the recesses;

forming a dielectric structure surrounding the sacrificial gate and the fin structure over the substrate;

removing a portion of the sacrificial gate to form a gate trench, wherein residue is formed in the gate trench; and

performing a third cleaning operation to remove the residue from the gate trench.