Liquid flow rate estimation and verification by direct liquid measurement
US5866795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1997 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Mar 17, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F25/17
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for controlling the flow of a liquid precursor into a deposition chamber comprises a liquid injection system having a liquid injection outlet connected to a chamber inlet line upstream of the deposition chamber. The liquid injection system includes a liquid precursor supply, a purge gas supply, a carrier gas supply, a liquid flow meter, and a controller managing flows of the liquid precursor and carrier gas to the chamber. A purge line is connected between the purge gas supply and the liquid flow meter and is used to trap a known mass of liquid precursor. To calibrate the flow of the liquid precursor, the purge gas is used to push the trapped liquid precursor through the liquid flow meter at a steady rate. The elapsed time for evacuating the trapped liquid precursor from the purge line is measured. Calibration information is computed using the mass of the trapped liquid precursor and the measured elapsed time based on the direct liquid measurement approach. The calibration information is used to calibrate the controller to correct deviations in the liquid flow rate and achieve a target liquid precursor flow rate for improving wafer uniformity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.