US 12,276,033 B2
Methods for wet etching of noble metals
Paul Abel, Austin, TX (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Nov. 14, 2022, as Appl. No. 17/986,160.
Application 17/986,160 is a continuation in part of application No. 17/674,579, filed on Feb. 17, 2022, granted, now 11,802,342.
Claims priority of provisional application 63/257,226, filed on Oct. 19, 2021.
Prior Publication US 2023/0121246 A1, Apr. 20, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C23F 1/30 (2006.01)
CPC C23F 1/30 (2013.01) 24 Claims
OG exemplary drawing
 
1. A method of etching, the method comprising:
receiving a substrate having a noble metal formed thereon, wherein a noble metal surface is exposed on a surface of the substrate;
exposing the surface of the substrate to a surface modification solution such that the surface modification solution is in contact with the noble metal surface, wherein the surface modification solution includes a persulfate salt, a chloride ion source and a cation, and wherein the persulfate salt reacts with the chloride ion source to form dichloride radical ions, which oxidize the noble metal surface to form a noble metal salt passivation layer;
removing the surface modification solution from the surface of the substrate subsequent to forming the noble metal salt passivation layer;
exposing the surface of the substrate to a dissolution solution that reacts with the noble metal salt passivation layer to form soluble species that are dissolved by the dissolution solution; and
removing the dissolution solution and the soluble species from the substrate.