US 11,901,220 B2
Bilayer seal material for air gaps in semiconductor devices
Shuen-Shin Liang, Hsinchu County (TW); Chen-Han Wang, Zhubei (TW); Keng-Chu Lin, Chao-Chou Ping-Tung (TW); Tetsuji Ueno, Hsinchu (TW); and Ting-Ting Chen, New Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Jul. 23, 2020, as Appl. No. 16/937,237.
Claims priority of provisional application 62/951,809, filed on Dec. 20, 2019.
Prior Publication US 2021/0193506 A1, Jun. 24, 2021
Int. Cl. H01L 21/768 (2006.01); H01L 29/66 (2006.01)
CPC H01L 21/7682 (2013.01) [H01L 21/76826 (2013.01); H01L 21/76828 (2013.01); H01L 21/76831 (2013.01); H01L 21/76832 (2013.01); H01L 29/6656 (2013.01); H01L 29/66795 (2013.01); H01L 29/6653 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for forming a semiconductor device, comprising:
forming a first sidewall structure by forming an L-shaped spacer on a sidewall of a gate structure;
forming a second sidewall structure by forming another spacer on a sidewall of a source/drain structure, wherein:
the second sidewall structure is opposite to the first sidewall structure, and
the first and second sidewall structures are formed of different layers and define boundaries of an opening;
depositing a first dielectric material at a first deposition rate on top portions of the opening;
depositing a second dielectric material at a second deposition rate on the first dielectric material and on the first and second sidewall structures, wherein the second dielectric material and the first and second sidewall structures entrap a pocket of air; and
performing a treatment process on the second dielectric material.