An extreme ultraviolet light generation apparatus includes a chamber including a first space and a second space; a first partition wall including a first opening through which extreme ultraviolet light passes; a connection portion connecting the chamber and an external apparatus; a second partition wall including a second opening through which the extreme ultraviolet light passes; a gas supply port which allows a gas to pass therethrough; a first exhaust port which opens to the first space; a second exhaust port which opens to a third space located inside the connection portion; a first sensor arranged in the third space; and a processor calculating a first passage flow rate of a gas passing through the first opening based on a measurement result of the first sensor and adjusting a supply flow rate of the gas to be supplied through the gas supply port based on the first passage flow rate.

A light source apparatus, in which an energy beam transforms a liquid raw material into plasma to extract radiation, includes a rotation body, a raw material supply section, and a layer thickness adjustment section. The rotation body is disposed at a position onto which the energy beam is incident, and includes a groove overlapping with an incident area of the energy beam. The raw material supply section supplies the groove with the liquid raw material. The layer thickness adjustment section adjusts a layer thickness of the liquid raw material such that a front surface of the liquid raw material forms a concave surface in response to the groove in the incident area of the energy beam.

A light source includes a light generating chamber and a collector disposed in the light generating chamber. A target material generator configured to propel a quantity of target material toward an irradiation region is disposed in front of a reflective surface of the collector. A plurality of photodetector modules is disposed external to the light generating chamber, with each of the photodetector modules being directed toward the irradiation region. A plurality of tubes is disposed between a corresponding photodetector module and the irradiation region. Each tube has a centerline directed toward the irradiation region, and each tube has a roughened inner surface. The surface roughness of the roughened inner surface is sufficient to cause grazing incidences of light to be eliminated rather than to be reflected off the roughened inner surface. A method of generating light and a method of measuring light energy also are described.

A reflective EUV optic such as a collector mirror configured as an array of facets that are spaced apart to form respective gaps between adjacent facets. The gaps are used as inlets for gas flow across one of the facets such that flow is introduced parallel to the optic surface. The facets can be made with offsets such that loss of reflective area of the EUV optic can be minimized. The gas facilitates removal of target material from the surface of the facets.

A chamber for an extreme ultraviolet light generation apparatus is a chamber into which droplets are sequentially outputted, and may include an image capturing unit configured to repeatedly capture images of the droplets during an image capturing time set so that images of two adjacent droplets that have been outputted do not overlap.

An extreme ultraviolet light generation apparatus includes a chamber, a target supply unit supplying a droplet of a target substance toward a plasma generation region, a light concentrating mirror concentrating extreme ultraviolet light, a debris shield provided with a first opening through which the extreme ultraviolet light passes from the plasma generation region toward the light concentrating mirror and a second opening, a gas supply port supplying a gas to an internal space of the chamber, and an exhaust port exhausting a gas in a space surrounded by the debris shield. At least a part of the second opening is provided at a position symmetrical to at least a part of the first opening with reference to a plane including a trajectory of the laser light and a trajectory of the droplet. The gas at the internal space flows into the space through the first opening and the second opening.

A target supply system includes a load lock chamber configured to contain a solid target substance, a solid target supply pipe connected to the load lock chamber, a pressure regulator configured to regulate an externally supplied gas pressure, a gas pressure supply pipe connected to the pressure regulator, a melting tank connected to both the solid target supply pipe and the gas pressure supply pipe, and configured to melt the solid target substance supplied from the load lock chamber via the solid target supply pipe to generate a liquid target substance, a nozzle configured to discharge the liquid target substance by a gas pressure supplied from the pressure regulator to the melting tank via the gas pressure supply pipe, and a buffer tank configured to communicate with the melting tank and supply a gas pressure thereto when the solid target substance is supplied to the melting tank.

An extreme ultraviolet light generation system, generating extreme ultraviolet light by irradiating a target substance with laser light, includes a tank storing the target substance in a liquid state, a nozzle outputting the target substance stored in the tank, a piezoelectric element applying vibration to the target substance to be output from the nozzle to generate droplets of the target substance, a droplet detection device detecting a time interval of passage of the droplets output from the nozzle, and at least one processor. The processor acquires a first value of a vibration parameter relating to the vibration of the piezoelectric element, acquires a variation of the time interval corresponding to each of a plurality of values including the first value of the vibration parameter, and generates the droplets using a second value with which the variation of the time interval is smaller than that with the first value.

A radiation system configured to produce radiation and comprising a droplet generator (3) configured to produce a droplet of fuel traveling towards a plasma formation region, a laser system operative to generate a pre-pulse (PP) and a main pulse (MP), wherein the pre-pulse is configured to condition the droplet for receipt of the main pulse, and wherein the main pulse is configured to convert the conditioned droplet into plasma producing the radiation and a control system configured to control a spatial offset between the pre-pulse and the droplet in a plane transverse to a propagation direction of the pre-pulse, wherein the control system is configured to adjust the spatial offset so as to maximize a velocity change of the conditioned droplet in a plane transverse to a propagation direction of the main pulse.

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.