Reduction, reclaim and reuse of sulfuric acid in piranha cleans

In semiconductor manufacturing, sulfuric acid is used in piranha solution (Sulfuric acid and hydrogen peroxide mixture, SPM). SPM is typically dispensed on silicon wafer substrate for removal of organic residue. In this work, we describe and discuss ways to a) reduce sulfuric acid consumption b) reclaim sulfuric acid and c) optimize cleaning process to control sulfuric acid concentration in the sulfuric collection system so it can be reused by other industries.