Ruthenium-etching solution, method for manufacturing ruthenium-etching solution, method for processing object to be processed, and method for manufacturing ruthenium-containing wiring
A ruthenium-etching solution for carrying out an etching process on ruthenium. The etching solution includes orthoperiodic acid and ammonia, in which a pH is 8 or higher and 10 or lower. A method for manufacturing the ruthenium-etching solution, a method for processing an object to be processed including carrying out an etching process on an object to be processed including ruthenium using the ruthenium-etching solution, and a method for manufacturing a ruthenium-containing wiring.
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.
2. The ruthenium-etching solution according to claim 1 , wherein the etching process is not a chemical mechanical polishing (CMP) process.
3. The ruthenium-etching solution according to claim 1 , wherein the etching process is a process for applying a substrate including an area formed of an insulate film and an area formed of ruthenium in a surface layer, thereby selectively etching the area formed of ruthenium.
4. A method for manufacturing the ruthenium-etching solution according to claim 1 , the method comprising, in the following order:
preparing a mixed solution by mixing a solution including orthoperiodic acid with aqueous ammonia, and adjusting a pH of the mixed solution to more than 8 and 9.5 or lower; and
filtering the mixed solution with a filter.
5. A method for processing an object to be processed, the method comprising carrying out an etching process on an object to be processed including ruthenium, using the ruthenium-etching solution according to claim 1 .
6. A method for manufacturing a ruthenium-containing wiring, the method comprising applying the ruthenium-etching solution according to claim 1 to a substrate including an area formed of an insulating film and an area formed of ruthenium in a surface layer, thereby selectively etching the area formed of ruthenium.