Energy efficient lithography laser
US6320892A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1999 |
| Grant date | Nov 20, 2001 |
| Priority date | — |
| Expiry date | Oct 18, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/2256
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An excimer laser system with an automatic fluorine control system to permit precise control of the fluorine concentration within an F.sub.2 "sweet spot" in a gas discharge laser chamber. This is done with a computer control system which monitors laser parameters, determines .DELTA.E/.DELTA.V, the change of pulse energy with voltage, and automatically and precisely controls the fluorine concentration based on .DELTA.E/.DELTA.V without the need to actually measure the fluorine concentration. The present invention is especially useful in lithography environments in which photo resist having a wide range of sensitivity are used. The present invention permits operation of the laser at substantially maximum efficiency over a wide range of pulse energy outputs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.