US 12,463,050 B2
Methods for wet atomic layer etching of molybdenum
Tulashi Dahal, Austin, TX (US); Paul Abel, Austin, TX (US); and Mengistie Debasu, Austin, TX (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Aug. 30, 2023, as Appl. No. 18/240,142.
Prior Publication US 2025/0079180 A1, Mar. 6, 2025
Int. Cl. H01L 21/311 (2006.01); H01L 21/02 (2006.01)
CPC H01L 21/31111 (2013.01) [H01L 21/0206 (2013.01); H01L 21/02068 (2013.01); H01L 21/02175 (2013.01); H01L 21/02244 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method of etching, the method comprising:
receiving a substrate having a molybdenum (Mo) layer formed thereon, wherein a molybdenum surface is exposed on a surface of the substrate;
exposing the surface of the substrate to a surface modification solution comprising an oxidizer dissolved in a non-aqueous solvent, wherein the oxidizer reacts with the molybdenum surface to oxidize the molybdenum surface and form a molybdenum oxide passivation layer, which is self-limiting and insoluble in the non-aqueous solvent;
removing the surface modification solution from the surface of the substrate subsequent to forming the molybdenum oxide passivation layer;
exposing the surface of the substrate to a dissolution solution to selectively remove the molybdenum oxide passivation layer, wherein the dissolution solution reacts with the molybdenum oxide passivation layer to form soluble species that are dissolved by the dissolution solution, wherein the dissolution solution is an aqueous acidic solution, an aqueous basic solution or a non-aqueous ligand solution; and
removing the dissolution solution and the soluble species from the surface of the substrate to etch the molybdenum layer.