Chemical-mechanical polishing slurry formulation and method for tungsten and titanium thin films

• Main Authors: WOO; CHRISTY MEIU, SCHONAUER; DIANA MARIE, BURKE; PETER AUSTIN, AVANZINO; STEVEN C
• Format: Patent
• Language: English
• Published: 29.06.1999
• Edition: 6
• Subjects: ADHESIVES; BASIC ELECTRIC ELEMENTS; CHEMISTRY; DYES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; POLISHES; POLISHING COMPOSITIONS OTHER THAN FRENCH POLISH; SEMICONDUCTOR DEVICES; SKI WAXES

A polishing slurry composition and its method of making for planarization of silicon semiconductor wafers by chemical mechanical polishing of the wafer. A slurry formulation utilizing a ferric salt tungsten oxidizer, an ammonium persulfate titanium oxidizer, a fatty acid suspension agent, alumina particles with a small diameter and tight diameter range, coated with a solubility coating, and a chemical stabilizer, provides high tungsten and titanium polish rates with high selectivity to silicon dioxide, and good oxide defectivity for use in tungsten local interconnect applications. A method for making a tungsten slurry includes first thoroughly blending small diameter alumina particles with a tight diameter range in an aqueous concentrate with a suspension agent, then mixing with water and oxidizers. Ferric salt tungsten slurries made by this method provide excellent tungsten polish characteristics for via plug and local interconnect applications.