Photon source, metrology apparatus, lithographic system and device manufacturing method

An inspection apparatus comprising:

• a support configured to support a substrate, the substrate having a structure thereon;
• an optical system configured to illuminate the structure under predetermined illumination conditions and to detect radiation diffracted by the structure under the predetermined illumination conditions;
• a processor configured to process information characterizing the detected radiation to obtain a measurement of a property of the structure, wherein the optical system includes a photon source apparatus comprising:
• a container configured to contain a gaseous atmosphere;
• a driving system configured to form a driving radiation beam focused on a plasma forming zone within the container and maintain, by the driving radiation beam, a plasma in an elongated form having a length along a longitudinal axis that is substantially greater than a diameter of the elongated form in a direction transverse to the longitudinal axis;
• and
• a collecting optical system configured to collect photons emitted from an end of the plasma along the longitudinal axis and to form the collected photons into at least one beam of output radiation.

A lithographic system comprising:

• a lithographic apparatus comprising:
• an illumination optical system configured to illuminate a pattern;
• a projection optical system configured to project an image of the pattern onto a substrate;
• and
• an inspection apparatus comprising:
• a support configured to support the substrate, the substrate having a structure thereon;
• an optical system configured to illuminate the structure under predetermined illumination conditions and to detect radiation diffracted by the structure under the predetermined illumination conditions;
• a processor configured to process information characterizing the detected radiation to obtain a measurement of a property of the structure,
• wherein the optical system includes a photon source apparatus comprising:
• a container configured to contain a gaseous atmosphere;
• a driving system configured to form a driving radiation beam focused on a plasma forming zone within the container and maintain, by the driving radiation beam, a plasma in an elongated form having a length along a longitudinal axis that is substantially greater than a diameter of the elongated form in a direction transverse to the longitudinal axis;
• and
• a collecting optical system configured to collect photons emitted from an end of the plasma along the longitudinal axis and to form the collected photons into at least one beam of output radiation,
• wherein the lithographic apparatus is arranged to use the measurement results from the inspection apparatus in applying the pattern to further substrates.

A method comprising:

• generating a driving radiation beam focused on a plasma forming zone within a container containing a gaseous atmosphere;
• maintaining, by the driving radiation beam, a plasma in an elongated form having a length along a longitudinal axis that is substantially greater than a diameter of the elongated form in a direction transverse to the longitudinal axis;
• collecting photons, by a collecting optical system, emitted from an end of the plasma along the longitudinal axis;
• and
• forming the collected photons into at least one beam of output radiation.

A method of manufacturing a device, comprising:

• generating a driving radiation beam focused on a plasma forming zone within a container containing a gaseous atmosphere;
• maintaining, by the driving radiation beam, a plasma in an elongated form having a length along a longitudinal axis that is substantially greater than a diameter of the elongated form in a direction transverse to the longitudinal axis;
• collecting photons, by a collecting optical system, emitted from an end of the plasma along the longitudinal axis;
• forming the collected photons into at least one beam of output radiation;
• illuminating a structure using the beam of output radiation;
• detecting radiation diffracted by the structure;
• determining, from a property of the diffracted radiation, a property of the structure;
• and
• controlling a lithographic process for later substrates in response to the determined property.