Regeneration process of etching solution, etching process, and etching system

• Main Authors: MURATA, MITSUGU, IZUTA, NOBUHIKO
• Format: Patent
• Language: Chinese; English
• Published: 01.04.2004
• Subjects: ADHESIVES; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; DYES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25; NATURAL RESINS; NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; PAINTS; POLISHES; SEMICONDUCTOR DEVICES

A regeneration process is disclosed for an etching solution composed of a phosphoric acid solution and used in etching silicon nitride films in an etch bath. As a result of the etching, the etching solution contains a silicon compound. According to the regeneration process, the etching solution with a silicon compound contained therein is taken out of the etch bath. Water is then added to the taken-out etching solution to lower a concentration of phosphoric acid in the etching solution to 80 to 50 wt.%. By the lowing of the concentration of phosphoric acid, the silicon compound is caused to precipitate. The thus-precipitated silicon compound is removed from the etching solution. An etching process making use of the regeneration process and an etching system suitable for use in practicing the regeneration process and etching process are also disclosed.