Polarizing beam splitter device, interferometer module, lithographic apparatus, and device manufacturing method

An interferometer module, comprising:

• a polarizing beam splitter device, comprising:
• (a) a continuous and monolithic optical element, including;
• (i) a retroreflector surface configured to retroreflect a beam of radiation that is internally incident on the retroreflector surface, said retroreflector surface comprising at least a first face, a second face, and a third face that are substantially planar faces and meet at a common point,
• (ii) a radiation beam passage surface configured to transmit a beam of radiation into or out of the optical element, said radiation beam passage surface comprising a fourth face that is substantially planar and is arranged opposite said common point and a fifth face that is substantially planar and is arranged at an angle with respect to said fourth face, and
• (iii) a handler surface configured to handle the polarizing beam splitter device without touching the retroreflector surface or the radiation beam passage surface, said handler surface comprising at least one surface that extends between said retroreflector surface and said radiation beam passage surface, and
• (b) a polarizing beam splitting layer disposed on said fourth face;
• (c) a second optical element having at least a first substantially planar face, wherein the polarizing beam splitter layer is sandwiched between said fourth face of the optical element and said at least first face of said second optical element, and
• (d) a non-polarizing beam splitter device, and
• a frame plate with a first side and a second side opposite the first side,
• wherein said polarizing beam splitter device is mounted on the first side of said frame plate, and the non-polarizing beam splitter device is mounted on the second side of said frame plate, and
• wherein said frame plate includes at least one aperture located between said polarizing beam splitter device and said non-polarizing beam splitter device.

An interferometer system configured to measure a displacement of an object, comprising:

• a laser beam source;
• a polarizing beam splitter device, comprising:
• (a) a continuous and monolithic optical element, including;
• (i) a retroreflector surface configured to retroreflect a beam of radiation that is internally incident on the retroreflector surface, said retroreflector surface comprising at least a first face, a second face, and a third face that are substantially planar faces and meet at a common point,
• (ii) a radiation beam passage surface configured to transmit a beam of radiation into or out of the optical element, said radiation beam passage surface comprising a fourth face that is substantially planar and is arranged opposite said common point and a fifth face that is substantially planar and is arranged at an angle with respect to said fourth face, and
• (iii) a handler surface configured to handle the polarizing beam splitter device without touching the retroreflector surface or the radiation beam passage surface, said handler surface comprising at least one surface that extends between said retroreflector surface and said radiation beam passage surface, and
• (b) a polarizing beam splitting layer disposed on said fourth face;
• wherein said handler surface comprises two separate and substantially planar mutually opposite faces that extend between said fourth face, said fifth face and said retroreflector surface;
• an optical receiver that is able to receive an optical signal;
• and
• a processing device that is constructed to convert said optical signal to a displacement value.

A lithographic apparatus comprising:

• a radiation system configured to condition a beam of radiation;
• a patterning device configured to pattern the beam of radiation;
• a substrate holder configured to hold a substrate;
• a projection system configured to project the beam of radiation onto a target portion on said substrate;
• and
• an interferometer system configured to measure a displacement of said substrate, said interferometer comprising:
• (a) a laser beam source;
• (b) a polarizing beam splitter device, comprising:
• (i) a continuous and monolithic optical element, including;
• (1) a retroreflector surface configured to retroreflect a beam of radiation that is internally incident on the retroreflector surface, said retroreflector surface comprising at least a first face, a second face, and a third face that are substantially planar faces and meet at a common point,
• (2) a radiation beam passage surface configured to transmit a beam of radiation into or out of the optical element, said radiation beam passage surface comprising a fourth face that is substantially planar and is arranged opposite said common point and a fifth face that is substantially planar and is arranged at an angle with respect to said fourth face, and
• (3) a handler surface configured to handle the polarizing beam splitter device without touching the retroreflector surface or the radiation beam passage surface, said handler surface comprising at least one surface that extends between said retroreflector surface and said radiation beam passage surface, and
• (ii) a polarizing beam splitting layer disposed on said fourth face
• wherein said handler surface comprises two separate and substantially planar mutually opposite faces that extend between said fourth face, said fifth face and said retroreflector surface;
• an optical receiver that is able to receive an optical signal;
• and
• a processing device that is constructed to convert said optical signal to a displacement value.

A device manufacturing method comprising:

• patterning a beam of radiation;
• projecting the beam of radiation onto a substrate;
• and
• measuring a displacement of said substrate with an interferometer system comprising;
• (a) a laser beam source;
• (b) a polarizing beam splitter device, comprising:
• (i) a continuous and monolithic optical element, including;
• (1) a retroreflector surface configured to retroreflect a beam of radiation that is internally incident on the retroreflector surface, said retroreflector surface comprising at least a first face, a second face, and a third face that are substantially planar faces and meet at a common point,
• (2) a radiation beam passage surface configured to transmit a beam of radiation into or out of the optical element, said radiation beam passage surface comprising a fourth face that is substantially planar and is arranged opposite said common point and a fifth face that is substantially planar and is arranged at an angle with respect to said fourth face, and
• (3) a handler surface configured to handle the polarizing beam splitter device without touching the retroreflector surface or the radiation beam passage surface, said handler surface comprising at least one surface that extends between said retroreflector surface and said radiation beam passage surface, and
• (ii) a polarizing beam splitting layer disposed on said fourth face
• wherein said handler surface comprises two separate and substantially planar mutually opposite faces that extend between said fourth face, said fifth face and said retroreflector surface;
• (b) an optical receiver that is able to receive an optical signal;
• and
• (c) a processing device that is constructed to convert said optical signal to a displacement value.

A polarizing beam splitter device comprising:

• a pyramidal retroreflector portion including a first, a second and a third substantially planar faces extending from an apex of said retroreflector portion, said first, second and third planar faces being substantially perpendicular to one another;
• and
• a beam splitter portion extending from a base of said pyramidal retroreflector portion, said beam splitter portion including:
• (a) a first and a second handler faces configured to handle said device, said first and second handler faces being substantially perpendicular to said base, and
• (b) a beam splitting face defining an angle substantially equal to 45° with an axis of symmetry extending from the apex of said pyramidal retroreflector portion, said beam splitting face being substantially covered with a polarizing beam splitting layer.