Deep ultra-violet light sources for wafer and reticle inspection systems
AssigneeKLA-Tencor Corporation
InventorsGang Lei, Damon F. Kvamme
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Abstract
Disclosed are methods and apparatus for generating a sub-208 nm laser. A laser apparatus includes one or more seed radiation sources for generating a first radiation beam having a first fundamental wavelength on a first optical path and a second radiation beam having a second fundamental wavelength on a second optical path, a first amplifier for amplifying the first radiation beam, a second amplifier for amplifying the second radiation beam, and a wavelength conversion module comprising a plurality of crystals for frequency multiplying and mixing the amplified first and second radiation beams to produce an output beam at a fifth harmonic that is less than about 208 nm.
Claims10
A laser apparatus for generating output radiation having a wavelength below about 208 nm, comprising:
- one or more seed radiation sources for generating a first radiation beam having a first fundamental wavelength on a first optical path and a second radiation beam having a second fundamental wavelength on a second optical path, wherein the first radiation beam has a wavelength between 800-850 nm or 905-940 nm and the second radiation beam has a wavelength between about 980-1120 nm;
- a first amplifier for amplifying the first radiation beam;
- a second amplifier for amplifying the second radiation beam;
- and
- a wavelength conversion module for frequency multiplying and mixing the amplified first and second radiation beams to produce an output beam at a fifth harmonic that is less than about 208 nm, wherein the wavelength conversion module comprises:
- a 2nd harmonic generator (2HG) for receiving the second radiation beam and generating a 2nd harmonic beam by doubling a frequency of the second radiation beam;
- a 3rd harmonic generator (3HG) for receiving and mixing the 2nd harmonic radiation beam with the second radiation beam to generate a 3rd harmonic beam;
- a 4th harmonic generator (4HG) for receiving and mixing the first radiation beam with the 3rd harmonic beam to generate a 4th harmonic beam;
- and
- a fifth harmonic generator (5HG) for generating the output beam at a 5th harmonic that is less than about 208 nm by receiving and mixing the 4th harmonic radiation beam and the first radiation beam.
A method of generating output radiation having a wavelength below about 208 nm, comprising:
- generating a first radiation beam having a first fundamental wavelength on a first optical path and a second radiation beam having a second fundamental wavelength on a second optical path, wherein the first radiation beam has a wavelength between 800-850 nm or 905-940 nm and the second radiation beam has a wavelength between about 980-1120 nm;
- amplifying the first radiation beam;
- amplifying the second radiation beam;
- and
- frequency multiplying and mixing the amplified first and second radiation beams to produce an output beam at a fifth harmonic that is less than about 208 nm, wherein the operation of multiplying and mixing is performed by:
- a 2nd harmonic generator (2HG) for receiving the second radiation beam and generating a 2nd harmonic beam by doubling a frequency of the second radiation beam;
- a 3rd harmonic generator (3HG) for receiving and mixing the 2nd harmonic radiation beam with the second radiation beam to generate a 3rd harmonic beam;
- a 4th harmonic generator (4HG) for receiving and mixing the first radiation beam with the 3rd harmonic beam to generate a 4th harmonic beam;
- and
- a fifth harmonic generator (5HG) for generating the output beam at a 5th harmonic that is less than about 208 nm by receiving and mixing the 4th harmonic radiation beam and the first radiation beam.
Dependencies are inferred from the claim text.