Copper etchant and method of etching

• Main Authors: AOKI MASUMI, ISHIKAWA MAKOTO, SAITOU NORIYUKI, KATSUKI TAKANOBU
• Format: Patent
• Language: Chinese; English
• Published: 02.01.2008
• 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

The present invention provides copper etchant and a method of etching which can perform selective uniform etching of copper or a copper alloy even when mixed with another metal. The copper etchant at least contains ammonium oxalate, hydrogen peroxide and a surfactant, and has a surface tension less than 45mN/m and PH from 6.0 to 8.5. The ammonium oxalate functions as a complex agent for dissolving copper in the form of a copper complex. The hydrogen peroxide functions as an oxidant for oxidizing a copper surface. The addition of the surfactant lowers the surface tension of the etchant below 45 mN/m. As a result, substrate surface wetting and etchant permeation into high-aspect portions of a substrate structure can be enhanced, and in the co-presence of a metal with high conductivity for wiring or electrode, copper or copper alloys can be etched uniformly and selectively.