# US 9,039,957 B2 · Target material refinement device and target supply apparatus

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- Number: US 9,039,957 B2
- Document ID: US9039957B2
- Status: Granted
- Kind: B2
- Application number: 13/770,939
- Filed: 2013-02-19
- Published: 2013-08-29
- Granted: 2015-05-26
- Earliest claimed: 2012-02-23
- Assignees: Gigaphoton Inc.
- Applicants: Gigaphoton Inc.
- Inventors: Yutaka Shiraishi; Osamu Wakabayashi
- Web page: https://patentgrep.com/patent/US9039957B2

## CPC

- C22B 9/00: General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- H05G 2/002: {Supply of the plasma generating material}
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- 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)

## Abstract

A target material refinement device may include a refinement tank to accommodate a target material, a heating section to heat the interior of the refinement tank, and an oxygen-atom removing section to remove oxygen atoms present in the target material.

## Claims

### Claim 1

A target material refinement device that refines a target material used for generation of EUV light, comprising:
a refinement tank configured to accommodate a target material;
a heating section configured to heat an interior of the refinement tank; and
an oxygen-atom removing section configured to remove oxygen atoms present in the target material, wherein
the oxygen-atom removing section includes:
a reduction section configured to reduce the oxygen atoms; and
an exhaust section to evacuate the interior of the refinement tank, and
the reduction section includes a gettering substance that generates oxidants with the oxygen atoms.

### Claim 2 (depends on 1)

The target material refinement device according to claim 1,
wherein the oxygen-atom removing section includes:
an oxygen partial-pressure adjusting section configured to control an oxygen partial pressure inside of the refinement tank to be lower than the oxygen partial pressure in the target material; and
the exhaust section configured to evacuate the interior of the refinement tank.

### Claim 3 (depends on 2)

The target material refinement device according to claim 2, wherein the oxygen partial-pressure adjusting section is an oxygen-free gas supply section configured to supply an oxygen-free gas into the refinement tank.

### Claim 4 (depends on 2)

The target material refinement device according to claim 2, wherein the oxygen partial-pressure adjusting section is configured with the exhaust section configured to evacuate the interior of the refinement tank to be in a vacuum state in the interior of the refinement tank.

### Claim 5 (depends on 1)

The target material refinement device according to claim 1,
wherein the oxygen-atom removing section includes:
an inert gas supply section configured to supply an inert gas into the target material; and
the exhaust section configured to evacuate the interior of the refinement tank.

### Claim 6 (depends on 1)

The target material refinement device according to claim 1,
wherein the oxygen-atom removing section includes:
a separating section configured to separate oxidants formed of the oxygen atoms and other elements; and
an oxidant removing section configured to remove the above oxidants.

### Claim 7 (depends on 6)

The target material refinement device according to claim 6, wherein the separating section is the heating section configured to control a melting temperature of the target material and separates oxidants formed of the oxygen atoms and the target material.

### Claim 8 (depends on 2)

A target supply apparatus comprising:
the target material refinement device according to claim 2; and
a nozzle which has a through-hole and is disposed so that the through-hole communicates with the interior of the refinement tank of the target material refinement device.

### Claim 9 (depends on 7)

A target supply apparatus comprising:
the target material refinement device according to claim 7;
a target generator configured to outputs a target material into a chamber where EUV light is generated;
a generator heating section configured to heat and melt the target material in the target generator;
a transfer section configured to transfer the target material in the refinement tank of the target material refinement device to the target generator; and
a target supply controller configured to control a temperature of the target material in the target generator to be higher than the temperature of the target material in the refinement tank.