An excimer laser apparatus according to the present disclosure includes a chamber configured to accommodate a laser gas and a pair of electrodes and generate pulse-oscillating laser light when the gas pressure of the laser gas is controlled in accordance with voltage applied between the pair of electrodes, a power supply configured to apply the voltage between the pair of electrodes, and a controller to which a target value of the spectral linewidth of the laser light is inputted, the controller configured to correct the voltage used to control the gas pressure, when the target value changes from a first target value to a second target value, based on a first function having the second target value as a parameter and control the gas pressure in accordance with the corrected voltage.

An excimer laser apparatus according to the present disclosure includes a chamber configured to accommodate a laser gas and a pair of electrodes and generate pulse-oscillating laser light when the gas pressure of the laser gas is controlled in accordance with voltage applied between the pair of electrodes, a power supply configured to apply the voltage between the pair of electrodes, and a controller to which a target value of the spectral linewidth of the laser light is inputted, the controller configured to correct the voltage used to control the gas pressure, when the target value changes from a first target value to a second target value, based on a first function having the second target value as a parameter and control the gas pressure in accordance with the corrected voltage.

A method of manufacturing a semiconductor includes generating plasma in an amplifying tube using gas as a gain medium; detecting a state of the plasma generated in the amplifying tube; determining a virtual laser gain based on the detected state of the plasma; controlling the state of the plasma such that the virtual laser gain is within a target range; and manufacturing the semiconductor device including performing an exposure process on a substrate using a laser beam output from the amplifying tube adjusted to have the virtual laser gain within the target range.

A gas laser apparatus includes a laser oscillator including a pair of discharge electrodes disposed to face each other and configured to generate light from laser gas upon application of voltage, and a laser-side resonator in which the light resonates; an amplifier including an amplification unit and an amplification-side resonator; a beam splitter configured to reflect a part of the light from the laser-side resonator; an optical sensor configured to detect the light reflected by the beam splitter; and a processor configured to control the voltage based on an output from the optical sensor. The amplification-side resonator includes a rear mirror and an output coupling mirror. The laser-side resonator includes a grating and an output coupling mirror. The processor maintains the voltage at a constant value equal to or larger than a threshold of the voltage when the voltage is to be smaller than the threshold.

A gas laser apparatus includes a laser oscillator including a pair of discharge electrodes disposed to face each other and configured to generate light from laser gas upon application of voltage, and a laser-side resonator in which the light resonates; an amplifier including an amplification unit and an amplification-side resonator; a beam splitter configured to reflect a part of the light from the laser-side resonator; an optical sensor configured to detect the light reflected by the beam splitter; and a processor configured to control the voltage based on an output from the optical sensor. The amplification-side resonator includes a rear mirror and an output coupling mirror. The laser-side resonator includes a grating and an output coupling mirror. The processor maintains the voltage at a constant value equal to or larger than a threshold of the voltage when the voltage is to be smaller than the threshold.

A line narrowing module includes a prism including an entrance side surface that light enters, an exit side surface from which the light is emitted, and a bottom surface, and configured to wavelength-disperse the light having entered the entrance side surface and to emit the light from the exit side surface; a holder portion having a stationary surface on which the bottom surface of the prism is secured; a rotary mechanism portion including a rotary stage on which the holder portion is secured, the rotary stage being configured to rotate the prism around an axis perpendicular to a dispersion plane of the light emitted from the prism; a drive unit configured to rotate the rotary stage; and a grating configured to reflect the light emitted from the prism, centroids of the prism, the holder portion, and the rotary stage being located on the axis.

A laser chamber apparatus may include a pipe, an inner electrode extending along a longitudinal direction of the pipe and disposed in a through hole in the pipe, an outer electrode including a contact plate extending along the longitudinal direction of the pipe and being in contact with an outer circumferential surface of the pipe and a ladder section formed of bar members each having one end connected to the contact plate and juxtaposed along a longitudinal direction of the contact plate, and a leaf spring extending along the longitudinal direction of the pipe and configured to press the outer electrode against the pipe. The leaf spring may include leaf spring pieces separated by slits, and the leaf spring pieces may each include a bent section bent along the edge and are configured to press the bar members in a position shifted from the bent sections toward the edge.

A system includes a laser source operable to provide a laser beam, a laser amplifier having a gain medium operable to provide energy to the laser beam when the laser beam passes through the laser amplifier, and a residual gain monitor operable to provide a probe beam and operable to derive a residual gain of the laser amplifier from the probe beam when the probe beam passes through the laser amplifier while being offset from the laser beam in time or in path.

A system includes an optical source configured to emit a pulsed light beam, the optical source comprising one or more chambers, each of the one or more chambers configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life; at least one detection module configured to: receive and analyze data related to the pulsed light beam, and produce a beam quality metric based on the data related to the pulsed light beam; and a monitoring module configured to: analyze the beam quality metric, determine a health status of the gaseous gain medium based on the analysis of the beam quality metric, and produce a status signal based on the determined health status, the status signal indicating whether to extend use of the gaseous gain medium beyond the assumed gas life or to end use of the gaseous gain medium.

A system includes an optical source configured to emit a pulsed light beam, the optical source comprising one or more chambers, each of the one or more chambers configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life; at least one detection module configured to: receive and analyze data related to the pulsed light beam, and produce a beam quality metric based on the data related to the pulsed light beam; and a monitoring module configured to: analyze the beam quality metric, determine a health status of the gaseous gain medium based on the analysis of the beam quality metric, and produce a status signal based on the determined health status, the status signal indicating whether to extend use of the gaseous gain medium beyond the assumed gas life or to end use of the gaseous gain medium.