Device and method for detecting reference spherical wave deviation in visible light point diffraction interferometer

A point-diffraction interferometer and reference sphere technology, used in measuring devices, optical radiation measurement, instruments, etc., can solve problems such as limited accuracy and inability to meet detection requirements, and achieve the effect of high-precision detection

Inactive Publication Date: 2011-12-28
CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI
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Problems solved by technology

[0003] The Hartmann wavefront sensor is usually used to measure the wavefront deviation, but its accuracy is very limited, and it cannot meet the requirements of the reference spherical wave deviation detection in the visible light point diffraction interferometer.

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  • Device and method for detecting reference spherical wave deviation in visible light point diffraction interferometer
  • Device and method for detecting reference spherical wave deviation in visible light point diffraction interferometer
  • Device and method for detecting reference spherical wave deviation in visible light point diffraction interferometer

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Embodiment Construction

[0024] Such as figure 1 As shown, the reference spherical wave deviation detection device in the visible light point diffraction interferometer of the present invention includes: a grating 2, a small hole plate 3 with three circular holes along the orthogonal direction, a CCD detector 5, a computer 6, The small hole plate 3 is located between the grating 2 and the CCD detector 5; the grating 2 diffracts the converging light wave 1 passing through it, and the diffracted light is diffracted by the small hole plate 3 and interferes and superimposed, and is detected by the CCD The interferogram is recorded on the detector 5; the computer 6 collects the recorded interferogram from the CCD detector 5 through the signal line.

[0025] Such as figure 2 , image 3 As shown, glass substrate 7, metal chromium (Cr) layer 8, three round holes: hole one 10, hole two 9 and hole three 11, hole one 10 is located in the center of the small orifice plate, hole two 9 is located at the center o...

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Abstract

The invention discloses a device and a method for detecting reference spherical wave deviation in a visible point diffraction interferometer and belongs to the field of reference spherical wave ultra-high precision detection methods. The limitation of a Hartmann wavefront sensor on wavefront micro-deviation detection is overcome so that the wavefront high-precision detection can be realized. A light path comprises an incidence convergent light wave, a grating, a small pore plate with three circular holes along an orthogonal direction and a charge coupled device. The output end of the charge coupled device is connected to a computer. After being diffracted through the grating, the incidence convergent light wave is divided into a plurality of diffraction orders; +/-1 order of diffraction light respectively passes through two small holes; after the light is diffracted by the small holes, approximately ideal spherical waves are generated; two spherical waves are subjected to shear interference; an interference image is recorded on a CCD (Charge Coupled Device) detector; and after the interference image is collected, the diffraction wavefront deviation can be obtained. According to the device and method disclosed by the invention, the diffraction wavefront high-precision detection is realized by performing the shear interface of the spherical waves generated through double-hole diffraction in a visible light band.

Description

technical field [0001] The invention belongs to the field of ultra-high-precision detection methods for reference spherical waves, that is, a method for detecting the deviation of reference spherical waves diffracted by a circular hole by using an interferometer. Background technique [0002] The EUV lithography projection objective contains several aspheric surfaces, and the polishing accuracy of each aspheric surface must reach 0.2nm RMS to 0.3nm RMS. Common commercial Fizeau interferometers or Tieman-Green interferometers are limited by reference components, and their detection accuracy is far from meeting the requirements of this ultra-high-precision detection task. The point diffraction interferometer (PDI) generates The reference spherical wave can achieve ultra-high-precision detection, and the detection accuracy that PDI can achieve mainly depends on the quality of the reference spherical wave. In practice, how to detect the deviation of the near-ideal reference sph...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01J9/02
Inventor 卢增雄金春水王丽萍
Owner CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI
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