System and method for controlling source laser firing in an LPP EUV light source
US9426872B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 2015 |
| Grant date | Aug 23, 2016 |
| Priority date | — |
| Expiry date | Aug 12, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G2/009
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Methods and systems for improved timing of a source laser in a laser produced plasma (LPP) extreme ultraviolet (EUV) generation system are disclosed. Due to forces within the plasma chamber, a velocity of a droplet can slow as it approaches the irradiation site. Because the droplet is slowed, a source laser fires prematurely relative to the slowed droplet, resulting in only a leading portion of the droplet being irradiated. The resulting amount of EUV energy generated from the droplet is proportional to the slowed velocity of the droplet. To compensate, the firing of the source laser is delayed for a next droplet based on the generated EUV energy. Because the firing of the source laser is delayed for the next droplet, the next droplet is more likely to be in position to be more completely irradiated, resulting in more EUV energy being generated from the next droplet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.