US 12,148,663 B2
Tiered-profile contact for semiconductor
Kisik Choi, Watervliet, NY (US); and Kangguo Cheng, Schenectady, NY (US)
Assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION, Armonk, NY (US)
Filed by International Business Machines Corporation, Armonk, NY (US)
Filed on Nov. 9, 2021, as Appl. No. 17/522,543.
Application 17/522,543 is a division of application No. 16/134,649, filed on Sep. 18, 2018, granted, now 11,195,753.
Prior Publication US 2022/0068713 A1, Mar. 3, 2022
Int. Cl. H01L 27/092 (2006.01); H01L 21/28 (2006.01); H01L 21/768 (2006.01); H01L 21/8238 (2006.01); H01L 23/528 (2006.01); H01L 23/535 (2006.01); H01L 29/08 (2006.01); H01L 29/10 (2006.01); H01L 29/49 (2006.01); H01L 29/66 (2006.01)
CPC H01L 21/76897 (2013.01) [H01L 21/28088 (2013.01); H01L 21/76805 (2013.01); H01L 21/76816 (2013.01); H01L 21/76895 (2013.01); H01L 21/823807 (2013.01); H01L 21/823814 (2013.01); H01L 21/823821 (2013.01); H01L 21/823842 (2013.01); H01L 21/823871 (2013.01); H01L 21/823878 (2013.01); H01L 23/5283 (2013.01); H01L 23/535 (2013.01); H01L 27/0924 (2013.01); H01L 29/0847 (2013.01); H01L 29/1054 (2013.01); H01L 29/4966 (2013.01); H01L 29/66545 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A structure, comprising:
a semiconductor device;
a first oxide layer disposed over the semiconductor device, wherein the first oxide layer is comprised of a first material, wherein the first material has a first etch rate property;
a second oxide layer disposed on the first oxide layer, wherein the second oxide layer is comprised of a second material, wherein the second material has a second etch rate property, wherein the second etch rate property is greater than the first etch rate property;
tiered-profile contacts extending through the first oxide layer and the second oxide layer down to the semiconductor device, wherein a bottom portion of the tiered-profile contacts passes through the first oxide layer and a top portion of the tiered-profile contacts passes through the second oxide layer, wherein the bottom tier of the tiered-profile contacts extends downwards past a bottom surface of the first oxide layer, and wherein the top portion of the tiered-profile contacts is wider than the bottom portion, wherein the first oxide layer is in direct contact with a sidewall of the top portion of the tiered-profile contacts and the second oxide layer is in direct contact with a sidewall of the bottom portion of the tiered-profile contacts;
a source and drain located beneath each of the tiered-profile contacts, wherein a bottom surface of the tiered-profile contacts to a top surface of the source and drains;
an etch stop located around the source and drains, wherein the etch stop is in contact with the sidewall of the bottom portion of the tiered-profile contacts; and
a gate spacer located adjacent to the bottom portion of the tiered-profile contacts.