Laser device, and extreme ultraviolet light generation system

Patent metadata

Field	Value
Publication number	US-10842008-B2
Application number	US-201916261313-A
Country	US
Kind code	B2
Filing date	Jan 29, 2019
Priority date	Sep 23, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A laser device includes at least one amplification unit configured to amplify laser light emitted from a laser oscillator, and an amplification control unit configured to control the amplification unit. The amplification unit includes an incident-side optical adjustment unit including a wavefront adjustment unit configured to adjust a wavefront of the laser light and a first direction adjustment unit configured to adjust an optical axis thereof, an amplifier configured to amplify the laser light, an emission-side optical adjustment unit including a second direction adjustment unit configured to adjust an optical axis of the laser light, and a measurement unit configured to measure the laser light and acquire information on at least one of an optical axis, a wavefront and energy of the laser light. The amplification control unit controls the incident-side optical adjustment unit and/or the emission-side optical adjustment unit, based on a measurement result of the measurement unit.

First claim

What is claimed is:

1. A laser device for an extreme ultraviolet light generation system, comprising:
amplification units configured to amplify laser light emitted from a laser oscillator; and
an amplification control unit configured to control the amplification units, each of the amplification units including:
an incident-side optical adjustment unit on which laser light is made incident, the incident-side optical adjustment unit including a wavefront adjustment unit configured to adjust a wavefront of the laser light, and a first direction adjustment unit configured to adjust an optical axis of the laser light;
an amplifier disposed downstream the incident-side optical adjustment unit in a transmission direction of the laser light, the amplifier being configured to amplify the laser light emitted from the incident-side optical adjustment unit;
an emission-side optical adjustment unit disposed downstream the amplifier in the transmission direction of the laser light, the emission-side optical adjustment unit including a second direction adjustment unit configured to adjust an optical axis of laser light emitted from the amplifier, the second direction adjustment unit being disposed at a position where the laser light emitted from the amplifier is directly made incident thereon; and
a measurement unit disposed downstream the emission-side optical adjustment unit in the transmission direction of the laser light, the measurement unit being configured to measure laser light emitted from the emission-side optical adjustment unit and acquire information on an optical axis, a wavefront and energy of the laser light, the measurement unit being disposed at a position where the laser light emitted from the second direction adjustment unit is directly made incident on the measurement unit,

the amplification control unit controlling the incident-side optical adjustment unit and the emission-side optical adjustment unit, based on a measurement result of the measurement unit, and
when the amplifier is replaced, the amplification control unit in response being configured to:
perform a first control of controlling the first direction adjustment unit such that energy of the laser light emitted from the amplifier after replacement increases;
determine a target value of the optimal optical axis and optimal wavefront of the laser light made incident on the amplification chamber, based on the first control for the first direction adjustment unit;
set the target value to the first direction adjustment unit; and then
perform a second control of controlling the second direction adjustment unit such that the optical axis of the laser light emitted from the amplifier after replacement approaches the optical axis before the amplifier is replaced, the optical axis before the amplifier is replaced being an optical axis of an amplification unit of a latter stage before the amplifier is replaced.

2. The laser device according to claim 1 , wherein
when the amplifier is replaced, the amplification control unit controls the wavefront adjustment unit such that a wavefront of the laser light emitted from the amplifier after replacement becomes a predetermined wavefront.

3. The laser device according to claim 1 , wherein
the measurement unit measures a direction of the optical axis and a passage position of the optical axis of the laser light to be measured.

4. The laser device according to claim 1 , wherein
when the amplifier is replaced, the amplification control unit controls the first direction adjustment unit to adjust the optical axis of the laser light, and then controls the wavefront adjustment unit to adjust a wavefront of the laser light with the optical axis thereof adjusted.

5. The laser device according to claim 1 , wherein
when the amplifier is replaced, the amplification control unit controls the first direction adjustment unit to adjust the optical axis of the laser light, and then controls the second direction adjustment unit such that an optical axis to be measured by the measurement unit approaches the optical axis before the amplifier is replaced.

6. The laser device according to claim 1 , wherein
the second direction adjustment unit is disposed at a position on which the laser light emitted from the amplifier is directly made incident, and the measurement unit is disposed at a position on which laser light emitted from the second direction adjustment unit is directly made incident.

7. The laser device according to claim 1 , wherein
the amplification units are arranged in series in the transmission direction of the laser light.

8. An extreme ultraviolet light source system for generating extreme ultraviolet light by irradiating a target substance with laser light to make the target substance into plasma, the system comprising:
amplification units configured to amplify laser light emitted from a laser oscillator;
an amplification control unit configured to control the amplification units; and
an extreme ultraviolet light generation chamber on which laser light emitted from the amplification units is made incident and in which extreme ultraviolet light is generated with use of the laser light,
each of the amplification units including:
an incident-side optical adjustment unit on which laser light is made incident, the incident-side optical adjustment unit including a wavefront adjustment unit configured to adjust a wavefront of the laser light, and a first direction adjustment unit configured to adjust an optical axis of the laser light;
an amplifier disposed downstream the incident-side optical adjustment unit in a transmission direction of the laser light, the amplifier being configured to amplify the laser light emitted from the incident-side optical adjustment unit;
an emission-side optical adjustment unit disposed downstream the amplifier in the transmission direction of the laser light, the emission-side optical adjustment unit including a second direction adjustment unit configured to adjust an optical axis of laser light emitted from the amplifier, the second direction adjustment unit being disposed at a position where the laser light emitted from the amplifier is directly made incident thereon; and
a measurement unit disposed downstream the emission-side optical adjustment unit in the transmission direction of the laser light, the measurement unit being configured to measure laser light emitted from the emission-side optical adjustment unit and acquire information on an optical axis, a wavefront and energy of the laser light, the measurement unit being disposed at a position where the laser light emitted from the second direction adjustment unit is directly made incident on the measurement unit,

the amplification control unit controlling the incident-side optical adjustment unit and the emission-side optical adjustment unit, based on a measurement result of the measurement unit, and
when the amplifier is replaced, the amplification control unit in response being configured to:
perform a first control of controlling the first direction adjustment unit such that energy of the laser light emitted from the amplifier after replacement increases;
determine a target value of the optimal optical axis and optimal wavefront of the laser light made incident on the amplification chamber, based on the first control for the first direction adjustment unit;
set the target value to the first direction adjustment unit; and then
perform a second control of controlling the second direction adjustment unit such that the optical axis of the laser light emitted from the amplifier after replacement approaches the optical axis before the amplifier is replaced, the optical axis before the amplifier is replaced being an optical axis of an amplification un

Assignees

• Gigaphoton Inc

Inventors

• Suganuma Takashi

Classifications

• H05G2/0086 Primary

  Optical arrangements for conveying the laser beam to the plasma generation location · CPC title

• H01S3/1302 Primary

  by all-optical means, e.g. gain-clamping · CPC title

• H01S3/2316

  Cascaded amplifiers · CPC title

• H01S3/1003

  tunable optical elements, e.g. acousto-optic filters, tunable gratings · CPC title

• G03F7/70033

  by plasma extreme ultraviolet [EUV] sources · CPC title