Discharge electrodes and light source device

Patent metadata

Field	Value
Publication number	US-10285253-B2
Application number	US-201615564328-A
Country	US
Kind code	B2
Filing date	Apr 1, 2016
Priority date	Apr 7, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

An extreme ultraviolet light source device includes a pair of disk-shaped discharge electrodes which face each other with their peripheral portions being spaced from each other, a pulsed power supply unit for supplying pulsed power to the discharge electrodes, a raw material supply unit for supplying onto the discharge electrodes raw materials that emit extreme ultraviolet light, and an energy beam irradiation unit for irradiating the raw materials on curved surfaces of the discharge electrodes with an energy beam to vaporize the raw materials. At least one of the paired discharge electrodes has a tapered surface at a peripheral portion of at least one of two circular surfaces thereof. The tapered surface inclines radially outward such that the thickness of the discharge electrode decreases in the radially outward direction.

First claim

The invention claimed is:

1. A pair of disc-shaped discharge electrodes for use in a light source device, one electrode in said pair of discharge electrodes having first and second flat circular surfaces, which are parallel to each other, and a first outer peripheral surface, which connects the first flat circular surface to the second flat circular surface, another one electrode in said pair of discharge electrodes having third and fourth flat circular surfaces, which are parallel to each other, and a second outer peripheral surface, which connects the third flat circular surface to the fourth flat circular surface, said pair of discharge electrodes disposed such that the first and second outer peripheral surfaces of said pair of discharge electrodes oppose each other with a predetermined space left therebetween, the light source device including said pair of discharge electrodes, a pulsed power supply unit that supplies pulsed power across the discharge electrodes, a source material supply unit that supplies onto the discharge electrodes a source material to radiate light, and an energy beam irradiation unit that irradiates the source material on one of the first and second outer peripheral surfaces of the discharge electrodes with an energy beam to vaporize the source material,
at least one of the discharge electrodes having a first inclined surface formed on at least one flat circular surface thereof, with the first and second outer peripheral surfaces being left, the first inclined surface being inclined such that a thickness of the discharge electrode decreases in a radially outward direction of the discharge electrode.

2. The pair of discharge electrodes according to claim 1 , wherein the first inclined surface having an angle of inclination corresponding to a take-off angle of the light from the discharge electrodes is provided on the flat circular surface located on a side toward which the light is extracted from the discharge electrodes.

3. The pair of discharge electrodes according to claim 2 , wherein the first inclined surface is provided on one flat circular surface among the first to fourth flat circular surfaces, and a second inclined surface having an angle of inclination corresponding to an angle of incidence of the energy beam on said one of the first and second outer peripheral surfaces of the discharge electrodes is provided on another flat circular surface among the first to fourth flat circular surfaces located on a side where a radiation source of the energy beam is installed.

4. The pair of discharge electrodes according to claim 2 , wherein said at least one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said at least one of the discharge electrodes and a second inclined surface provided on an opposite flat circular surface of the same discharge electrode, the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the second inclined surface.

5. The pair of discharge electrodes according to claim 2 , wherein said one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said one of the discharge electrodes, said another one of the discharge electrodes has a third inclined surface provided on one of the flat circular surfaces of said another one of the discharge electrodes, and the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the third inclined surface.

6. The pair of discharge electrodes according to claim 1 , wherein the first inclined surface having an angle of inclination corresponding to an angle of incidence of the energy beam on said one of the first and second outer peripheral surfaces of the discharge electrodes is provided on the flat circular surface located on a side where a radiation source of the energy beam is installed.

7. The pair of discharge electrodes according to claim 6 , wherein said at least one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said at least one of the discharge electrodes and a second inclined surface provided on an opposite flat circular surface of the same discharge electrode, the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the second inclined surface.

8. The pair of discharge electrodes according to claim 6 , wherein said one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said one of the discharge electrodes, said another one of the discharge electrodes has a third inclined surface provided on one of the flat circular surfaces of said another one of the discharge electrodes, and the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the third inclined surface.

9. The pair of discharge electrodes according to claim 1 , wherein said at least one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said at least one of the discharge electrodes and a second inclined surface provided on an opposite flat circular surface of the same discharge electrode, the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the second inclined surface.

10. The pair of discharge electrodes according to claim 9 , wherein said one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said one of the discharge electrodes, said another one of the discharge electrodes has a third inclined surface provided on one of the flat circular surfaces of said another one of the discharge electrodes, and the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the third inclined surface.

11. The pair of discharge electrodes according to claim 1 , wherein said one of the discharge electrodes has the first inclined surface provided on one of the flat circular surfaces of said one of the discharge electrodes, said another one of the discharge electrodes has a third inclined surface provided on one of the flat circular surfaces of said another one of the discharge electrodes, the angle of inclination of the first inclined surface is set to an angle different from the angle of inclination of the third inclined surface.

12. The pair of discharge electrodes according to claim 1 , wherein said one of the discharge electrodes has the first inclined surface provided on the first flat circular surface and a second inclined surface provided on the second flat circular surface, and said another one of the discharge electrodes has a third inclined surface on the third flat circular surface and a fourth inclined surface on the fourth circular surface.

13. The pair of discharge electrodes according to claim 12 , wherein an angle of inclination of the first inclined surface is equal to an angle of inclination of the second inclined surface, and an angle of inclination of the third inclined surface is equal to an angle of inclination of the fourth inclined surface.

14. The pair of discharge electrodes according to claim 12 , wherein an angle of inclination of the first inclined surface is different from an angle of inclination of the second inclined surface, and an angle of inclination of the third inclined surface is different from an angle of inclination of the fourth inclined surface.

15. The pair of discharge electrodes

Assignees

• Ushio Electric Inc

Inventors

• Teramoto Yusuke
• Nagano Akihisa
• URAKAMI Hideyuki

Classifications

• H05G2/003 Primary

  the plasma being generated from a material in a liquid or gas state · CPC title

• H05H1/46 Primary

  using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) · CPC title

• H05H2001/466

  Electricity · mapped topic

• H05G2/00

  Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma (X-ray lasers H01S4/00) · CPC title

• H05G2/008

  involving an energy-carrying beam in the process of plasma generation · CPC title