Patent ID: 11898081
Assignee: TOKYO OHKA KOGYO CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC C  H | IPC C  H

Claim 0:
1. A ruthenium-etching solution for carrying out an etching process on ruthenium, the ruthenium-etching solution comprising:
orthoperiodic acid; and
ammonia as the sole pH adjuster,
wherein a pH is more than 8 and 9.5 or lower,
the content of orthoperiodic acid is 0.5 to 3% by mass, and
a number of particles larger than 100 nm contained in the etching solution is 20 particles/ml or less, and
the ruthenium etching solution comprises no slurry and no abrasive,
wherein the ruthenium-etching solution is manufactured by a method consisting of:
dissolving orthoperiodic acid in water to obtain an orthoperiodic acid solution,
mixing the orthoperiodic acid solution with aqueous ammonia to adjust the pH of the mixed solution to more than 8 and 9.5 or lower, and
filtering the mixed solution with a filter.