US 12,176,400 B2
Backside contact with air spacer
Chen-Ming Lee, Taoyuan County (TW); and Wei-Yang Lee, Taipei (TW)
Assigned to TAIWAN SEMINCODCUTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on Jul. 24, 2023, as Appl. No. 18/357,637.
Application 18/357,637 is a continuation of application No. 17/813,822, filed on Jul. 20, 2022, granted, now 11,798,996.
Application 17/813,822 is a continuation of application No. 17/159,423, filed on Jan. 27, 2021, granted, now 11,444,162, issued on Sep. 13, 2022.
Prior Publication US 2023/0369419 A1, Nov. 16, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 29/40 (2006.01); H01L 21/283 (2006.01); H01L 21/3213 (2006.01); H01L 29/417 (2006.01); H01L 29/66 (2006.01); H01L 29/786 (2006.01)
CPC H01L 29/401 (2013.01) [H01L 21/283 (2013.01); H01L 21/32135 (2013.01); H01L 29/4175 (2013.01); H01L 29/66795 (2013.01); H01L 29/78696 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method, comprising:
receiving a workpiece comprising:
a substrate,
an active region over the substrate and including a source/drain feature, and
a dummy contact structure embedded in the substrate and below the active region;
performing a first etching process on a backside of the substrate to expose the dummy contact structure;
performing a deposition process to deposit a first dielectric layer around the dummy contact structure and below a bottom surface of the active region;
removing the dummy contact structure to form a trench;
depositing a sacrificial layer on sidewalls of the trench;
filling the trench with a conductive plug; and
removing the sacrificial layer to form an air spacer between the first dielectric layer and the conductive plug.