Composition for selectively polishing silicon nitride layer and polishing method employing it
US7217989B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 2005 |
| Grant date | May 15, 2007 |
| Priority date | — |
| Expiry date | Oct 18, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31053
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
To provide a polishing composition whereby the stock removal rate of a silicon nitride layer is higher than the stock removal rate of a silicon oxide layer, there is substantially no adverse effect against polishing planarization, and a sufficient stock removal rate of a silicon nitride layer is obtainable, and a polishing method employing such a composition. A polishing composition which has silicon oxide abrasive grains, an acidic additive and water, wherein the acidic additive is such that when it is formed into a 85 wt % aqueous solution, the chemical etching rate of the silicon nitride layer is at most 0.1 nm/hr in an atmosphere of 80° C. Particularly preferred is one wherein the silicon oxide abrasive grains have an average particle size of from 1 to 50 nm, and the pH of the composition is from 3.5 to 6.5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.