US Patent No. 10,893,599

LASER PRODUCED PLASMA LIGHT SOURCE HAVING A TARGET MATERIAL COATED ON A CYLINDRICALLY-SYMMETRIC ELEMENT


Patent No. 10,893,599
Issue Date January 12, 2021
Title Laser Produced Plasma Light Source Having A Target Material Coated On A Cylindrically-symmetric Element
Inventorship Alexey Kuritsyn, San Jose, CA (US)
Brian Ahr, San Jose, CA (US)
Rudy F. Garcia, Union City, CA (US)
Frank Chilese, San Ramon, CA (US)
Oleg Khodykin, San Diego, CA (US)
Assignee KLA Corporation, Milpitas, CA (US)

Claim of US Patent No. 10,893,599

1. A device comprising:a cylindrically-symmetric element rotatable about an axis and having a surface coated with a band of plasma-forming target material for irradiation by a drive laser to produce plasma;
a subsystem for replenishing plasma-forming target material on the cylindrically-symmetric element; and
a wiper positioned to scrape plasma-forming target material on the cylindrically-symmetric element to establish a uniform thickness of plasma-forming target material; and
a measurement system outputting a signal indicative of a radial distance between the wiper edge and the axis, wherein the measurement system comprises a light emitter and a light sensor.