US 12,243,749 B2
Methods to provide uniform wet etching of material within high aspect ratio features provided on a patterned substrate
Shan Hu, Albany, NY (US); Henan Zhang, Albany, NY (US); Sangita Kumari, Albany, NY (US); and Peter Delia, Albany, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Sep. 26, 2022, as Appl. No. 17/952,613.
Prior Publication US 2024/0105455 A1, Mar. 28, 2024
Int. Cl. H01L 21/306 (2006.01)
CPC H01L 21/30604 (2013.01) 20 Claims
OG exemplary drawing
 
1. A method of etching, the method comprising:
providing a patterned substrate having at least one feature formed within a material layer formed on the patterned substrate, wherein the at least one feature has a critical dimension (CD) and an etch depth; and
exposing the patterned substrate to an etch solution to etch the material layer and increase the CD and the etch depth of the at least one feature, wherein the etch solution comprises reactive ions and has a pH value;
wherein when exposed to the etch solution, wall surfaces of the material layer being etched exhibit a neutral surface charge substantially equal to 0 mV at the pH value of the etch solution, and wherein as a result of the neutral surface charge, a uniform concentration of the reactive ions is maintained within the at least one feature and uniform etching is provided along the etch depth of the at least one feature.