Methods for verifying gas flow rates from a gas supply system into a plasma processing chamber
US9234775B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 2013 |
| Grant date | Jan 12, 2016 |
| Priority date | — |
| Expiry date | Jun 12, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D7/0652
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods of measuring gas flow rates in a gas supply system for supplying gas to a plasma processing chamber are provided. In a differential flow method, a flow controller is operated at different set flow rates, and upstream orifice pressures are measured for the set flow rates at ambient conditions. The measured orifice pressures are referenced to a secondary flow verification method that generates corresponding actual gas flow rates for the different set flow rates. The upstream orifice pressures can be used as a differential comparison for subsequent orifice pressure measurements taken at any temperature condition of the chamber. In an absolute flow method, some parameters of a selected gas and orifice are predetermined, and other parameters of the gas are measured while the gas is being flowed from a flow controller at a set flow rate through an orifice. In this method, any flow controller set point can be flowed at any time and at any chamber condition, such as during plasma processing operations. Gas supply systems are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.