Interferometer and interferance measurement method

An interferometer for measuring a surface shape of an optical element using interference, said interferometer comprising:

• an elastically deformable mirror that has a variable surface shape, at a reference-light side;
• and
• a reference wave-front generating unit, at a object-light side, that may produce a wave front as a measurement reference of the surface shape.

An exposure apparatus using an optical element prepared by an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising a reference wave-front deformation system for deforming a wave front of reference light.

An exposure apparatus using an optical element prepared by an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising an elastically deformable mirror that has a variable surface shape, at a reference-light side, and a reference wave-front generating unit, at a object-light side, that may produce a wave front as a measurement reference of the surface shape.

An interference measuring method for measuring a surface shape of an optical element using an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising a reference wave-front deformation system for deforming a wave front of reference light.

An interference measuring method for measuring a surface shape of an optical element using an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising an elastically deformable mirror that has a variable surface shape, at a reference-light side, and a reference wave-front generating unit, at a object-light side, that may produce a wave front as a measurement reference of the surface shape.

An interferometer for measuring a surface shape of an optical element using interference, said interferometer comprising, at a reference-light side, two or more elastically deformable mirrors, each of which has a variable surface shape and thus can form a desired surface shape.

A wave-front forming method for obtaining a desired wave front from a surface of a first or second elastically deformable mirror, said method comprising the steps of:

• positioning the first elastically deformable mirror having a variable surface shape at a reference plane position, and the second elastically deformable mirror having a variable surface shape at a datum plane position, and varying a surface shape of the second elastically deformable mirror based on the surface shape of the first elastically deformable mirror using interference information between a first wave front from the surface of the first elastically deformable mirror and a second wave front from the surface of the second elastically deformable mirror;
• and
• after varying the surface shape of the first elastically deformable mirror by a predetermined amount, deforming, necessary times n (n is a natural number), the surface shape of the second elastically deformable mirror based on the surface shape of the first elastically deformable mirror using interference information between the first wave front from the surface of the first elastically deformable mirror and the second wave front from the surface of the second elastically deformable mirror.

An exposure apparatus using an optical element manufactured by using an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising, at a reference light side, two or more elastically deformable mirrors, each of which has a variable surface shape and thus can form a desired surface shape.

An interference measurement method for measuring a surface shape of an optical element by using an interferometer for measuring a surface shape of the optical element using interference, said interferometer comprising, at a reference light side, two or more elastically deformable mirrors, each of which has a variable surface shape and thus can form a desired surface shape.