US 12,482,667 B2
Thermal etching of ruthenium
Hisashi Higuchi, Nirasaki (JP); Kai-Hung Yu, Albany, NY (US); Cory Wajda, Albany, NY (US); Gyanaranjan Pattanaik, Albany, NY (US); Kandabara Tapily, Albany, NY (US); Gerrit Leusink, Albany, NY (US); and Robert Clark, Leuven (BE)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Oct. 31, 2023, as Appl. No. 18/385,522.
Claims priority of provisional application 63/423,761, filed on Nov. 8, 2022.
Prior Publication US 2024/0153781 A1, May 9, 2024
Int. Cl. H01L 21/32 (2006.01); H01L 21/02 (2006.01); H01L 21/311 (2006.01); H01L 21/3213 (2006.01)
CPC H01L 21/32136 (2013.01) [H01L 21/02175 (2013.01); H01L 21/02244 (2013.01); H01L 21/02252 (2013.01); H01L 21/02337 (2013.01); H01L 21/31122 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of etching, the method comprising:
providing a substrate containing a ruthenium metal layer thereon, the ruthenium metal layer having a ruthenium surface exposed on the substrate; and
exposing the substrate to a gas pulse sequence to etch the ruthenium metal layer, wherein said exposing the substrate to the gas pulse sequence includes:
a) exposing the substrate to a first gas pulse comprising an oxygen-containing gas to form a first non-volatile oxide surface layer on the ruthenium metal layer, wherein the first non-volatile oxide surface layer is not removed by the oxygen-containing gas;
b) exposing the substrate to a second gas pulse comprising a chlorine-containing gas to convert the first non-volatile oxide surface layer into a second non-volatile oxide surface layer, wherein the second non-volatile oxide surface layer is not removed by the chlorine-containing gas; and
c) exposing the substrate to a third gas pulse comprising a fluorine-containing gas to remove the second non-volatile oxide surface layer from the ruthenium surface to etch the ruthenium metal layer.