Chemical-mechanical polishing slurry formulation and method for tungsten and titanium thin films
US5916855A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1997 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Mar 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/3212
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.