Method for one-to-one polishing of silicon nitride and silicon oxide
US7629258B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Nov 22, 2006 |
| Grant date | Dec 8, 2009 |
| Priority date | — |
| Expiry date | Dec 1, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31053
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention provides a method of removing silicon nitride at about the same removal rate as silicon dioxide by CMP. The method utilizes a polishing slurry that includes colloidal silica abrasive particles dispersed in water and additives that modulate the silicon dioxide and silicon nitride removal rates such that they are about the same. In one embodiment of the invention, the additive is lysine or lysine mono hydrochloride in combination with picolinic acid, which is effective at a pH of about 8. In another embodiment of the invention, the additive is arginine in combination with picolinic acid, which is effective at a pH of about 10.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.