Laser device, and exposure device and inspection device provided with laser device

Patent metadata

Field	Value
Publication number	US-9608400-B2
Application number	US-201314417986-A
Country	US
Kind code	B2
Filing date	Jul 31, 2013
Priority date	Jul 31, 2012
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A laser device, includes: a laser light generating unit generates laser lights with first and second wavelengths; an amplifying unit amplifies the lights with first and second wavelengths the first and the second amplified lights; a wavelength converting unit that generates a light output, either of first converted light wavelength conversion of the first amplified light and the second amplified light, or of the first converted light and the second converted light wavelength conversion of the second amplified light; and a control unit that controls operation of the laser light generating unit, wherein: the control unit controls an output condition of the light output by adjusting a temporal overlap, of the first converted light and the second amplified light, or the first and second converted lights, through control of relative timings of the laser light with the first and second wavelengths.

First claim

The invention claimed is:

1. A laser device, comprising:
a laser light generating unit that includes a first light source that generates pulse laser light with a first wavelength and a second light source that generates pulse laser light with a second wavelength;
an amplifying unit equipped with an amplifier achieving gain in light in a wavelength range that includes the first wavelength and the second wavelength, which outputs first amplified light obtained by amplifying the laser light with the first wavelength and second amplified light obtained by amplifying the laser light with the second wavelength;
a wavelength converting unit that converts light from one wavelength to another wavelength, the wavelength converting unit including a wavelength conversion optical element, which either converts the first amplified light to first converted light through wavelength conversion and generates a light output through wavelength conversion of the first converted light and the second amplified light or converts the first amplified light to first converted light and the second amplified light to second converted light and generates a light output through wavelength conversion of the first converted light and the second converted light; and
a control unit that controls operation of the laser light generating unit, wherein:
the control unit controls an output condition of the light output by adjusting a temporal overlap of the first converted light and the second amplified light or a temporal overlap of the first converted light and the second converted light at a position at which the light output is generated in the wavelength converting unit, through control of timing with which the laser light with the first wavelength is output from the first light source and the timing with which the laser light with the second wavelength is output from the second light source relative to each other; and
a wavelength of the light output from the wavelength converting unit is different from the first wavelength and is also different from the second wavelength.

2. The laser device according to claim 1 , wherein:
the wavelength converting unit includes a first wavelength conversion optical element that converts the first amplified light to first converted light through wavelength conversion and allows the second amplified light to be transmitted and a second wavelength conversion optical element that generates second converted light through wavelength conversion of the second amplified light transmitted through the first wavelength conversion optical element and the first converted light; and
the control unit controls an output condition of the second converted light by adjusting a temporal overlap of the first converted light and the second amplified light at the second wavelength conversion optical element through control of the timing with which the laser light with the first wavelength is output from the first light source and the timing with which the laser light with the second wavelength is output from the second light source relative to each other.

3. The laser device according to claim 2 , wherein:
the first wavelength and the second wavelength are individually set to such values that a phase matching condition for generating a sum frequency of the first converted light and the second amplified light is satisfied and a phase matching condition for generating a sum frequency of the first converted light and the first amplified light is not satisfied at the second wavelength conversion optical element.

4. The laser device according to claim 2 , wherein:
the first wavelength and the second wavelength are individually set to such values that a phase matching condition for generating a harmonic of the first amplified light is satisfied and a phase matching condition for generating a harmonic of the second amplified light is not satisfied at the first wavelength conversion optical element.

5. The laser device according to claim 2 , wherein:
the control unit controls ON/OFF of the second converted light provided as the light output by switching between a condition in which the first converted light and the second amplified light temporally overlap and a condition in which the first converted light and the second amplified light do not temporally overlap at the second wavelength conversion optical element.

6. The laser device according to claim 2 , wherein:
the control unit controls power of the second converted light provided as the light output by altering the extent to which the first converted light and the second amplified light temporally overlap at the second wavelength conversion optical element.

7. The laser device according to claim 1 , wherein:
the wavelength converting unit includes a first wavelength conversion optical element that converts the first amplified light to first converted light through wavelength conversion and allows the second amplified light to be transmitted, a second wavelength conversion optical element that converts the second amplified light having been transmitted through the first wavelength conversion optical element to second converted light through wavelength conversion and allows the first converted light to be transmitted, and a third wavelength conversion optical element that generates third converted light through wavelength conversion of the first converted light and the second converted light; and
the control unit controls an output condition of the third converted light by adjusting a temporal overlap of the first converted light and the second converted light at the third wavelength conversion optical element through control of the timing with which the laser light with the first wavelength is output from the first light source and the timing with which the laser light with the second wavelength is output from the second light source relative to each other.

8. The laser device according to claim 7 , wherein:
the first wavelength and the second wavelength are individually set to such values that a phase matching condition for generating a sum frequency of the first converted light and the second converted light is satisfied and any of phase matching conditions for generating sum frequencies and second harmonics other than the sum frequency is not satisfied at the third wavelength conversion optical element.

9. The laser device according to claim 7 , wherein:
the first wavelength and the second wavelength are individually set to such values that a phase matching condition for generating a harmonic of the first amplified light is satisfied and a phase matching condition for generating a harmonic of the second amplified light is not satisfied at the first wavelength conversion optical element and that a phase matching condition for generating a harmonic of the second amplified light is satisfied and a phase matching condition for generating a harmonic of the first amplified light is not satisfied at the second wavelength conversion optical element.

10. The laser device according to claim 7 , wherein:
the control unit controls ON/OFF of the third converted light provided as the light output by switching between a condition in which the first converted light and the second converted light temporally overlap and a condition in which the first converted light and the second amplified light do not temporally overlap at the third wavelength conversion optical element.

11. The laser device according to claim 7 , wherein:
the control unit controls power of the third converted light provided as the light output by altering the extent to which the first converted light and the second converted light temporally overlap at the third wavelength conversion optical element.

Assignees

• Nikon Corp

Inventors

• Tokuhisa Akira

Classifications

• H01S5/06216

  Pulse modulation or generation · CPC title

• H01S5/0683

  by monitoring the optical output parameters · CPC title

• H01S3/06754

  Fibre amplifiers (H01S3/06708 takes precedence) · CPC title

• G03F7/70058

  Mask illumination systems · CPC title

• G01N21/88

  Investigating the presence of flaws or contamination · CPC title