# US 9,439,276 B2 · Extreme ultraviolet light generating system

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- Number: US 9,439,276 B2
- Document ID: US9439276B2
- Status: Granted
- Kind: B2
- Application number: 14/937,332
- Filed: 2015-11-10
- Published: 2016-03-03
- Granted: 2016-09-06
- Earliest claimed: 2013-06-20
- Assignees: Gigaphoton Inc.
- Applicants: Gigaphoton Inc.
- Inventors: Takayuki Yabu; Takashi Saito; Osamu Wakabayashi
- Web page: https://patentgrep.com/patent/US9439276B2

## CPC

- H05G 2/0086: {Optical arrangements for conveying the laser beam to the plasma generation location}
- G03F 7/2006: {using coherent light; using polarised light}
- G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources}
- H05G 2/0027: {Arrangements for controlling the supply; Arrangements for measurements}
- H05G 2/0084: {Control of the laser beam}
- H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321)
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

There is provided an extreme ultraviolet light generating system. The extreme ultraviolet light generating system may include: a laser apparatus configured to provide pulsed laser light inside a chamber in which EUV light is generated; an optical shutter disposed on an optical path of the pulsed laser light; and a controller configured to open or close the optical shutter, based on a generation signal supplied from an external unit, the generation signal instructing generation of the EUV light.

## Claims

### Claim 1

An extreme ultraviolet light generating system comprising:
a laser apparatus configured to provide pulsed laser light inside a chamber in which EUV light is generated;
an optical shutter disposed on an optical path of the pulsed laser light;
a controller configured to open or close the optical shutter, based on a generation signal supplied from an external unit, the generation signal instructing generation of the EUV light;
a light emission trigger generator configured to generate a light emission trigger signal and to supply the light emission trigger signal to the laser apparatus, the light emission trigger signal instructing output of the pulsed laser light;
a target feeder configured to feed a target inside the chamber, the target being to be irradiated with the pulsed laser light outputted from the laser apparatus;
a detector configured to detect feed timing at which the target is fed from the target feeder and to provide the light emission trigger generator with a first timing signal indicating the feed timing; and
a timer circuit configured to generate a second timing signal and to provide the light emission trigger generator with the second timing signal, during absence of the first timing signal from the detector,
wherein the light emission trigger generator generates the light emission trigger signal, based on the first timing signal and the second timing signal.

### Claim 2 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein
the optical shutter comprises a plurality of optical shutter devices, and
the controller controls the plurality of optical shutter devices to allow open timings or close timings to be different each other, depending on positions of the respective optical shutter devices on the optical path of the pulsed laser light.

### Claim 3 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein
the laser apparatus comprises a plurality of laser units,
the optical shutter comprises a plurality of optical shutter devices, and
the optical shutter devices are disposed on respective optical paths of the pulsed laser light output from the plurality of laser units.

### Claim 4 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein the laser apparatus continuously outputs the pulsed laser light irrespective of presence or absence of the supply of the generation signal.

### Claim 5 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein the optical shutter comprises an optical isolator.

### Claim 6 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein the light emission trigger generator includes a first OR circuit, the first OR circuit being coupled to the timer circuit and configured to receive the first timing signal and the second timing signal.

### Claim 7 (depends on 1)

The extreme ultraviolet light generating system according to claim 1, wherein the timer circuit outputs the second timing signal to the light emission trigger generator, when the absence of the first timing signal from the detector exceeds a time interval in which the target is fed.

### Claim 8 (depends on 6)

The extreme ultraviolet light generating system according to claim 6, wherein the light emission trigger generator includes:
a second OR circuit configured to receive the first timing signal and the second timing signal; and
a delay circuit coupled to the second OR circuit.

### Claim 9 (depends on 8)

The extreme ultraviolet light generating system according to claim 8, wherein the delay circuit generates the light emission trigger signal.

### Claim 10 (depends on 8)

The extreme ultraviolet light generating system according to claim 8, wherein the light emission trigger generator includes a first one-shot circuit configured to receive the second timing signal.

### Claim 11 (depends on 10)

The extreme ultraviolet light generating system according to claim 10, wherein the light emission trigger generator includes:
an inverter; and
a third OR circuit configured to receive an output signal of the first one-shot circuit through the inverter.

### Claim 12 (depends on 11)

The extreme ultraviolet light generating system according to claim 11, wherein the third OR circuit receives the generation signal.

### Claim 13 (depends on 12)

The extreme ultraviolet light generating system according to claim 12, wherein the third OR circuit outputs an optical shutter control signal that opens or closes the optical shutter.

### Claim 14 (depends on 10)

The extreme ultraviolet light generating system according to claim 10, wherein a length of a pulse width of an output signal of the first one-shot circuit is longer than a time in which the pulsed laser light passes through the optical shutter after the light emission trigger signal is inputted to the laser apparatus.

### Claim 15 (depends on 11)

The extreme ultraviolet light generating system according to claim 11, wherein the light emission trigger generator includes:
an AND circuit configured to receive the light emission trigger signal outputted from the delay circuit; and
a second one-shot circuit configured to receive the light emission trigger signal outputted from the delay circuit.

### Claim 16 (depends on 15)

The extreme ultraviolet light generating system according to claim 15, wherein the AND circuit receives the output signal of the third OR circuit.