US 12,261,170 B2
Semiconductor devices and methods of manufacturing thereof
Shih-Yao Lin, New Taipei (TW); Hsiao Wen Lee, Hsinchu (TW); Yu-Shan Cheng, Hsinchu (TW); and Ming-Ching Chang, Hsinchu (TW)
Assigned to Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed on Jun. 29, 2023, as Appl. No. 18/344,580.
Application 18/344,580 is a division of application No. 17/145,830, filed on Jan. 11, 2021, granted, now 11,721,693.
Prior Publication US 2023/0352479 A1, Nov. 2, 2023
Int. Cl. H01L 27/088 (2006.01); H01L 21/8234 (2006.01)
CPC H01L 27/088 (2013.01) [H01L 21/823418 (2013.01); H01L 21/823456 (2013.01); H01L 21/823481 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for making a semiconductor device, comprising:
forming a first fin structure in a first area of a substrate and a second fin structure in a second area of the substrate, wherein a first density of transistors formed in the first area is greater than a second density of transistors formed in the second area, and wherein the first fin structure includes a first stack of alternating sacrificial layers and channel layers and the second fin structure includes a second stack of the alternating sacrificial layers and channel layers; and
forming a first isolation structure in the first area and a second isolation structure in the second area, wherein the first isolation structure has a first height and the second isolation structure has a second height, the first height being greater than the second height, and wherein a bottommost sacrificial layer of the first stack is separated from a top surface of the first isolation structure by a first distance and a bottommost sacrificial layer of the second stack is separated from a top surface of the second isolation structure by a second distance, the first distance being less than the second distance.