Patent ID: 9241395
Filing Date: 2016-01-19
CPC Classification: H05G

Claim Text:
1. A system for timing firing of a source laser in an EUV LPP light source having a droplet generator which releases a droplet at a predetermined speed, the source laser firing pulses at an irradiation site, comprising: a droplet illumination module comprising a first line laser for generating a first laser curtain between the droplet generator and the irradiation site; a droplet detection module comprising a first sensor for detecting a flash from the first laser curtain when a droplet passes through the first laser curtain; and a first controller for determining, based upon the flash from the first laser curtain, the distance from the first curtain to the irradiation site, and the speed of the droplet, when the source laser should fire a pulse so as to irradiate the droplet when the droplet reaches the irradiation site, and generating a timing signal instructing the source laser to fire at such time.