Abstract: An extreme ultraviolet light generation apparatus includes a first chamber, an EUV light concentrating mirror arranged in the first chamber and configured to concentrate extreme ultraviolet light generated at a first point in the first chamber onto a second point, a first planar mirror arranged on an optical path of the extreme ultraviolet light reflected by the EUV light concentrating mirror, a second chamber accommodating the first planar mirror, a flexible tube arranged between the first and second chambers, an alignment optical system arranged at the first chamber and configured to cause alignment light to be incident on the EUV light concentrating mirror, a detector arranged at the second chamber and configured to detect the alignment light reflected by the EUV light concentrating mirror, an actuator configured to change posture of the first planar mirror, and a processor configured to control the actuator based on output of the detector.

Abstract: An extreme ultraviolet light generation apparatus includes a chamber in which a target is turned into plasma to generate extreme ultraviolet light, a target generator, an illumination device, and an imaging device receiving illumination light and capturing a target image. The imaging device includes a first transfer optical system transferring the target image, a mask having an opening formed at a transfer position of the first transfer optical system, a second transfer optical system transferring the target image at the opening, an image intensifier arranged such that a photoelectric surface is located at a transfer position of the second transfer optical system, a third transfer optical system transferring the target image at a fluorescent surface, an image sensor arranged at a transfer position of the third transfer optical system, and a moving mechanism capable of moving the mask by an amount equal to or larger than the opening.