Endpoint detection by chemical reaction and light scattering
US6194230A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 1998 |
| Grant date | Feb 27, 2001 |
| Priority date | — |
| Expiry date | May 6, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/26
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively produces a gaseous chemical reaction product (for example ammonia when polishing a wafer with a nitride film in a slurry containing KOH) with one of the stopping film and the target film, mixing the gaseous chemical reaction product present with a separate gas to form solid particles, and monitoring the amount of the solid particles as the target film is removed. Also, detection of a substance at very low concentrations in a liquid, by extracting the substance present as a gas from the liquid, mixing the gas with another substance to form solid particles, and monitoring the amount of the solid particles to detect the substance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.