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US 9,804,101 B2Granted
System and method for reducing the bandwidth of a laser and an inspection system and method using a laser
AssigneeKLA-Tencor Corporation
InventorsYujun Deng, Yung-Ho Chuang, John Fielden
Life of this patent
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Abstract
A DUV laser includes an optical bandwidth filtering device, such as etalon, which is disposed outside of the laser oscillator cavity of the fundamental laser, and which directs one range of wavelengths into one portion of a frequency conversion chain and another range of wavelengths into another portion of the frequency conversion train, thereby reducing the bandwidth of the DUV laser output while maintaining high conversion efficiency in the frequency conversion chain.
Claims12
A laser comprising:
- a fundamental laser configured to generate a fundamental wavelength with a fundamental wavelength bandwidth;
- a frequency conversion module configured to receive a first portion of the fundamental wavelength and to use the first portion as pump light to generate a second wavelength;
- a harmonic conversion module configured to generate a harmonic wavelength by converting a second portion of the fundamental wavelength;
- a frequency mixing module configured to mix the second wavelength with the harmonic wavelength to generate a sum wavelength shorter than 200 nm;
- and
- an optical bandwidth filtering device positioned to receive the fundamental wavelength from the fundamental laser and configured to generate the first portion and the second portion from the fundamental wavelength such that the second portion comprises a narrower range of wavelengths within the fundamental wavelength bandwidth than the first portion.
3 more elements
A method of generating deep UV laser radiation, the method comprising:
- generating a fundamental laser light having a fundamental wavelength and a fundamental wavelength bandwidth;
- separating the fundamental laser light into a first portion and a second portion such that the second portion comprises a narrower range of wavelengths within the fundamental wavelength bandwidth than the first portion;
- using the first portion as pump light to generate a second wavelength;
- generating a harmonic wavelength by converting the second portion;
- and
- summing the second wavelength and the harmonic wavelength to generate a deep UV output wavelength.
3 more elements
Dependencies are inferred from the claim text.