Method and apparatus for calibrating mass flow controllers
US8089046B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 2008 |
| Grant date | Jan 3, 2012 |
| Priority date | — |
| Expiry date | Jun 9, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F25/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining the flow rate of a gas includes measuring a first concentration of a calibration gas provided to the process chamber at a first pressure and temperature by directing infrared radiation into the process chamber and monitoring a first amount of infrared radiation absorbed by the calibration gas. A mixture of a second gas and the calibration gas is provided to the process chamber while maintaining the first pressure and temperature. A second concentration of the calibration gas in the mixture is measured by directing infrared radiation into the process chamber and monitoring a second amount of infrared radiation absorbed by the calibration gas. A flow rate of the second gas is calculated by comparing the first and second concentrations of the calibration gas. In one embodiment, the calibration gas and the second gas may not absorb the infrared radiation at the same wavelength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.