US Patent No. 10,143,075

DEVICE FOR EMITTING EXTREME ULTRAVIOLET LIGHT


Patent No. 10,143,075
Issue Date November 27, 2018
Title Device For Emitting Extreme Ultraviolet Light
Inventorship Yusuke Teramoto, Gotenba (JP)
Hideyuki Urakami, Himeji (JP)
Akihisa Nagano, Gotenba (JP)
Assignee USHIO DENKI KABUSHIKI KAISHA, Tokyo (JP)

Claim of US Patent No. 10,143,075

1. A light source device for emitting extreme ultraviolet light from plasma, comprising:a pair of disc-shaped rotatable discharge electrodes spaced from each other, each said disc-shaped rotatable discharge electrode having opposite circular surfaces and a circumferential surface lying between the opposite circular surfaces;
a power supply unit configured to supply the pair of discharge electrodes with pulsed power;
a pair of containers associated with the pair of discharge electrodes, respectively, each said container being configured to contain a high-temperature plasma raw material therein, the raw material being a liquid raw material;
a pair of raw material supply units associated with the pair of containers, respectively, each said raw material supply unit being configured to supply the high-temperature plasma raw material from the associated container onto the associated discharge electrode by allowing a portion of the associated discharge electrode to pass through the high-temperature plasma raw material in the associated container upon rotations of the discharge electrode concerned;
an energy beam irradiating unit configured to irradiate the high-temperature plasma raw material on the circumferential surface of one of said pair of discharge electrodes with an energy beam to vaporize the high-temperature plasma raw material such that electric discharge takes place between said pair of discharge electrodes to generate the plasma; and
a pair of film thickness regulating units associated with the pair of discharge electrodes, respectively, each said film thickness regulating unit being configured to regulate a thickness of the high-temperature plasma raw material on the circumferential surface of the associated discharge electrode to a predetermined film thickness, each said film thickness regulating unit including:
a film thickness regulating member that faces the circumferential surface of the associated discharge electrode with a predetermined gap;
a biasing member operable to bias the film thickness regulating member toward the circumferential surface of the associated discharge electrode; and
a control member operable to limit a movement of the film thickness regulating member biased by the biasing member in a biasing direction of the biasing member such that a gap between the circumferential surface of the associated discharge electrode and the film thickness regulating member becomes equal to or greater than a value corresponding to the predetermined film thickness,
wherein the control member and the biasing member are disposed on opposite sides of the film thickness regulating member, respectively.