In order to prevent observed long-term energy decay of power amplifiers and correspondingly increase the lifespan of CO.sub.2 lasers employing them, a hydrogen-doped mixing gas is supplied from an external pipeline during operation or periodic maintenance in order to effectively remove solid contaminants that build-up over time on a surface of a catalyst disposed within the power amplifier.

A pulsed-discharge radiation source includes a gas chamber, a window, and a conduit system. The conduit system includes a refill path and a conduit. The pulsed-discharge radiation source generates radiation. The gas chamber confines a gas and contaminants produced during the generation of radiation. The window isolates the gas from an environment external to the gas chamber and allows the radiation to travel between the gas chamber and the environment. The refill path allows a replacement of the gas. The conduit circulates the gas to or from the gas chamber during the generating. The conduit system directs a flow of one of a refill gas, the gas, or the refill gas and the gas at least during a refill operation to prevent the contaminant from contacting the window, whereby the conduit system increases the usable lifetime of at least the window.

An extreme ultraviolet light generation system includes a chamber, a target supply unit supplying a target substance to a plasma generation region including a first point in the chamber, a window allowing pulse laser light with which the target substance is irradiated to pass therethrough, an EUV light concentrating mirror concentrating extreme ultraviolet light generated at the first point on a second point, a planar mirror arranged on an optical path of the extreme ultraviolet light reflected by the EUV light concentrating mirror and between the first and second points, an actuator causing the second point to be switched between a first position and a second position, a connection portion connectable to an external apparatus, a first EUV measurement unit on which the extreme ultraviolet light having passed through the second position is incident, and a processor controlling the actuator based on a signal from the external apparatus.

A system and method for providing a radiation source. In one arrangement, the radiation source includes an optical fiber that is hollow, and has an axial direction, a gas that fills the hollow of the optical fiber, and a plurality of temperature setting devices disposed at respective positions along the axial direction of the optical fiber, wherein the temperature setting devices are configured to control the temperature of the gas to locally control the density of the gas.

A wavelength control method of a laser apparatus includes sequentially obtaining target wavelength data of a pulse laser beam, sequentially saving the target wavelength data, sequentially measuring a wavelength of the pulse laser beam to obtain a measured wavelength, calculating a wavelength deviation using the measured wavelength and the target wavelength data at a time before a time when the measured wavelength is obtained, and feedback-controlling the wavelength of the pulse laser beam using the wavelength deviation.

Systems for cleaning optical surfaces of overlay inspection systems are disclosed. In particular, systems for optical-path coupling of light for in-situ photochemical cleaning in projection imaging systems are disclosed. A system for cleaning optical surfaces of overlay inspection systems includes a first illumination source, a detector, a set of illumination optics, and a set of imaging optics. In some embodiments, the system may include at least one of a second illumination source and a third illumination source, each of which may be configured to cause or aid the removal of contaminants from one or more optical surfaces of the system.

A laser apparatus includes a first optical element, a second optical element, a first actuator configured to change a first wavelength component included in a pulse laser beam by changing a posture of the first optical element, a second actuator configured to change a second wavelength component included in the pulse laser beam by changing a posture of the second optical element, a first encoder configured to measure a position of the first actuator, a second encoder configured to measure a position of the second actuator, and a processor. The processor reads a first relation and a second relation and performs control of the first actuator based on the first relation and the position of the first actuator measured by the first encoder and control of the second actuator based on the second relation and the position of the second actuator measured by the second encoder.

Information relating to an etalon is accessed, the etalon being associated with a calibration parameter having a pre-set default value, the etalon being configured to produce an interference pattern including a plurality of fringes from a received light beam, and the information relating to the etalon including first spatial information related to a first fringe of the plurality of fringes and second spatial information related to a second fringe of the plurality of fringes. A first wavelength value of the received light beam is determined based on the spatial information related to the first fringe and an initial value of the calibration parameter. A second wavelength value of the received light beam is determined based on the spatial information related to the second fringe and the initial value of the calibration parameter. The first wavelength value and the second wavelength value are compared to determine a measurement error value.

The inventive concept provides a substrate treating apparatus. The substrate treating apparatus includes a support unit configured to support and rotate a substrate at a treating space; a liquid supply unit configured to supply a liquid to the substrate supported at the support unit; a housing having an installation space; a laser unit configured to include a laser irradiation unit positioned in the installation space which irradiates a laser light, and an irradiation end having an end positioned to protrude from the housing and which irradiates the laser light irradiated from the laser irradiation unit to a substrate supported on the support unit; and a cover having an inner space and positioned so an end of the irradiation end protruding from the housing is positioned in the inner space, and wherein an opening is formed at a bottom end of the cover to overlap the laser light irradiated from the irradiation end when seen from above.

A laser printhead assembly for a laser printhead is disclosed herein. The laser printhead assembly may include a laser containment door; and a laser containment housing that is configured to form a sealed enclosure with a label support of a rewriteable label. The sealed enclosure may be configured to include the rewriteable label and the laser printhead. The laser containment door, in a laser-enabled position, may be configured to permit the laser printhead, via a light beam, to modify the rewriteable label and the laser containment door, in a laser-disabled position, may be configured to prevent a light beam from escaping the laser containment housing.