A lithography system is provided capable of deterring contaminants, such as tin debris from entering into the scanner. The lithography system in accordance with various embodiments of the present disclosure includes a processor, an extreme ultraviolet light source, a scanner, and a hollow connection member. The light source includes a droplet generator for generating a droplet, a collector for reflecting extreme ultraviolet light into an intermediate focus point, and a light generator for generating pre-pulse light and main pulse light. The droplet generates the extreme ultraviolet light in response to the droplet being illuminated with the pre-pulse light and the main pulse light. The scanner includes a wafer stage. The hollow connection member includes an inlet that is in fluid communication with an exhaust pump. The hollow connection member provides a hollow space in which the intermediate focus point is disposed. The hollow connection member is disposed between the extreme ultraviolet light source and the scanner.

Degradation of the reflectivity of one or more reflective optical elements in a system (SO) for generating EUV radiation is reduced by the controlled introduction of a gas into a vacuum chamber (26) containing the optical element. The gas may be added to the flow of another gas such as hydrogen or alternated with the introduction of hydrogen radicals.

A method of controlling an extreme ultraviolet (EUV) lithography system is disclosed. The method includes irradiating a target droplet with EUV radiation, detecting EUV radiation reflected by the target droplet, determining aberration of the detected EUV radiation, determining a Zernike polynomial corresponding to the aberration, and performing a corrective action to reduce a shift in Zernike coefficients of the Zernike polynomial.

Systems, apparatuses, and methods are provided for steering aligning a laser beam and a fuel target. An example method can include generating, at a first rate, first sensing data indicative of a first overlap between a fuel target and a laser beam. The example method can further include generating, at a second rate, second sensing data indicative of a second overlap between the fuel target and the laser beam. The method can further include generating, at a third rate, and based on the first sensing data and the second sensing data, a steering control signal configured to steer the laser beam or the fuel target. In some aspects, the second rate can be different from the first rate, and the third rate can be about equal to the first rate. In other aspects, the first rate and the second rate can be about equal to the third rate.

A light source for EUV is provided. The light source includes a target droplet generator, a laser generator, and a controller. The target droplet generator is configured to provide target droplets to a source vessel. The laser generator is configured to provide first laser pulses according to a control signal to irradiate the target droplets in the source vessel. The controller is configured to provide the control signal according to at least two of process parameters including temperature of the source vessel, droplet positions of the target droplets, and beam sizes and focal points of the first laser pulses. When the average value or the standard deviation of the temperature of the source vessel and the droplet positions of the target droplets exceed the predetermined range, the controller is configured to provide the control signal to the laser generator to stop providing the first laser pulses.

A target image capturing device according to an aspect of the present disclosure includes a delay circuit configured to receive a timing signal from outside and output a first trigger signal at a timing delayed by a first delay time from the reception of the timing signal; an illumination light source configured to emit light based on the first trigger signal; an image capturing unit including a light amplification unit and disposed to capture an image of a shadow of a target to be observed, which is generated when the target is irradiated with the light emitted from the illumination light source; a processing unit configured to perform image processing including processing of measuring a background luminance from the image captured by the image capturing unit; and a control unit configured to perform control to adjust a gain of the light amplification unit based on the background luminance.

An extreme ultraviolet light generation apparatus includes a chamber; a housing extending from an internal space of the chamber to outside of the chamber, surrounding a plasma generation region except on a trajectory of a droplet target and on an optical path of laser light, and including a first opening through which extreme ultraviolet light generated from the plasma passes; a light concentrating mirror arranged in a first space outside the housing at the internal space and reflecting the extreme ultraviolet light having passed through the first opening in a direction different from an incident direction of the extreme ultraviolet light; and a gas supply port provided in the chamber; and a gas exhaust port provided at the housing outside the chamber. An optical axis of the laser light when being radiated to the droplet target is along a direction in which the gas flows in the plasma generation region.

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.

An amplified optical beam is provided to a region that receives a target including target material, an interaction between the amplified optical beam and the target converting at least some of the target material from a first form to a second form to form a light-emitting plasma; first data comprising information related to the amplified optical beam is accessed; second data comprising information related to the light-emitting plasma is accessed; and an amount of the target material converted from the first form to the second form is determined. The determination is based on at least the first data and the second data, and the second form of the target material is less dense than the first form of the target material.

An extreme ultraviolet light generation system may include a chamber, a first partition wall having at least one opening which provides communication between a first space and a second space, an EUV light concentrating mirror located in the second space and configured to concentrate extreme ultraviolet light generated in a plasma generation region located in the first space, a first gas supply port formed at the chamber, and a gas exhaust port formed in the first partition wall, a distance between the center of the plasma generation region and an edge of the at least one opening being equal to or more than a stop distance L.sub.STOP [mm] calculated by the following equation.

L.sub.STOP=272.8.Math.E.sub.VG.sup.0.4522.Math.P.sup.−1

E.sub.AVG [eV] representing average kinetic energy of ions generated in the plasma generation region and P [Pa] representing a gas pressure inside the first partition wall