Method for detecting an endpoint for an oxygen free plasma process
US6492186B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 1999 |
| Grant date | Dec 10, 2002 |
| Priority date | — |
| Expiry date | Nov 5, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3342
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining an endpoint for an oxygen free plasma stripping process for use in semiconductor wafer processing. The method comprises exciting a gas composition containing a nitrogen gas and a reactive gas to form the oxygen free plasma. The oxygen free plasma reacts with a substrate having a photoresist and/or residues thereon to produce emitted light signals corresponding to an oxygen free reaction product. The endpoint is determined by optically measuring a primary emission signal of the oxygen free reaction product at a wavelength of about 387 nm. The endpoint is determined when the plasma no longer reacts with the photoresist and/or residues on the substrate to produce the emitted light at about 387 nm, an indication that the photoresist and/or residues have been removed from the wafer. Secondary emission signals of the oxygen free reaction product at about 358 nm and 431 nm can also be monitored for determining the endpoint.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.