METHOD FOR STRIPPING LAYERS OF ORGANIC MATERIAL

摘要

1427482 Persuiphuric acid INTERNATIONAL BUSINESS MACHINES CORP 3 April 1974 [24 May 1973] 14697/74 Heading C1A [Also in Divisions B6 and G2] A liquid for removing organic material from substrates is prepared by mixing sulphuric acid containing at least 95% H 2 SO 4 by weight with an aqueous solution of hydrogen peroxide containing at least 30% H 2 O 2 by weight in such proportions that the ratio of H 2 SO 4 to H 2 O 2 is at least 15 : 1, preferably between 17 : 1 and 35 : 1. The ratio of the H 2 O 2 content to the water content of the sulphuric acid is preferably at least 11:1. The sulphuric acid and hydrogen peroxide react to form Caro acid (H 2 SO 5 ) and water, and the concentration of Caro acid resulting is preferably 3-10%. The liquid is suitable for stripping positive or negative photoresist from a semi-conductor substrate.