Bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect

A technology of bifocal zone plate and detection plane, which is applied in the directions of measuring devices, optical testing flaws/defects, using optical devices, etc., to achieve the effects of reducing quality requirements, improving utilization rate, and ensuring accuracy

Inactive Publication Date: 2015-06-24
NANJING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

3) Dual-wavelength interferometer method: This method is feasible in principle, and there are reports of test results in this area, but there is no commercialized dual-wavelength interferometer applied to flat mask detection

Method used

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  • Bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect
  • Bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect
  • Bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect

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Embodiment

[0027] A device for detecting defects in a planar mask by bifocal zone plate interference microscopy, including a 632.8nm laser light source 1, an aperture stop 2, a positive lens 3 with a focal length of 50 mm, and a semi-transparent and semi-reflective beam splitter 4. Bifocal zone plate 5. Planar mask to be tested 6. CCD detector 7. The polarization-stabilized He-Ne laser has a working wavelength λ=632.8nm, a power of 1.5mw, and an output spot diameter of φ1mm. The laser source 1 is close to the aperture stop 2, and when the laser light is incident, a point light source is formed on the aperture stop 2. The beam splitter 4 is based on k9 glass, coated with a semi-transparent and semi-reflective dielectric film, and the dielectric film material is Sio 2 and Tio 2 . The aperture stop is located at the focal point of the positive lens 3 with a focal length of 50mm. The emitted light is parallel light. The inclination angle of the beamsplitter 4 is 45°. The diffracted light ...

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Abstract

The invention discloses a bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect. According to the apparatus, a light source, an aperture diaphragm, a positive lens, a semi-reflecting and semi-transmitting spectroscope, a bifocal wave zone plate, a flat mask to be detected, light passes through the aperture diaphragm to form a spot light source, and then passes through a positive lens to form parallel light, parallel light passes through the semi-reflecting and semi-transmitting spectroscope and realizes incidence on the bifocal wave zone plate, 0-grade diffracted light satisfies a refraction principle, +1 grade diffracted light realizes converge under regulation and control of a bifocal wave zone plate phase function, and light having the phase information of the surface of the flat mask to be detected is reflected to form a return light path. By employing a bifocal wave zone plate interference system of reference light and test light common path, bifocal wave zone plate realizes diffraction condition of coexistence focal length and no focal length, Compared with a several sheets lens transmission group system, quantity of the lens transmission groups can be reduced, The bifocal wave zone plate interference microscopic system realizes synchronous detection function of amplitude-type defect and phase-type defect.

Description

technical field [0001] The invention belongs to the field of plane mask interference detection, in particular to a bifocal zone plate interference microscope device for detecting plane mask defects. Background technique [0002] A plane is a commonly used optical part in optical systems and engineering instruments, and it is also a basic optical and geometric test object. Especially in the field of optical interferometry, the plane wave aberration standard is the basis of other various tests, so it is necessary to obtain a high-precision standard plane. The detection of the conventional Fizeau interferometer and the Tieman Green interferometer is relative to the reference surface, and the commercial reference surface is generally only λ / 20PV (about 6nmRMS). Due to the development and application of computers, the actual optical wavefront can be transformed into a digital wavefront, and digital processing such as addition, subtraction, rotation, decomposition and reconstruct...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/95G01B11/30G02B27/44
Inventor 高志山窦健泰王若言宋华清杨忠明王帅成金龙王凯亮王伟叶井飞袁群
Owner NANJING UNIV OF SCI & TECH
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