High purity phosphoric acid and process of producing the same

摘要

High purity phosphoric acid having an Sb content of 200 ppb or less and a sulfide ion content of 200 ppb or less as impurity contents on a 85 weight percent H3PO4 basis. The high purity phosphoric acid is useful as an etching solution for semiconductor devices having a silicon nitride film, an etching solution for liquid crystal display panels having an alumina film, a metallic aluminum etching solution, an alumina etching solution for ceramics, a raw material of phosphate glass for optical fiber, a food additive, and so forth. A metallic material having low capability of forming a lithium compound penetrates through the whole thickness of the active material layer 5.