Measurement method and device for large-curvature-radius non-zero-digit interference based on virtual Newton's ring

A technology of curvature radius and measurement method, which is applied in the field of optical measurement, can solve the problems of limited bifocal zone plate design, processing accuracy, and high measurement cost, and achieve the effect of weakening the influence, ensuring the accuracy of the experiment, and simplifying the experiment process

Inactive Publication Date: 2017-04-26
NANJING UNIV OF SCI & TECH
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Problems solved by technology

This method is limited by the bifocal zone plate design and processing accuracy, and the measurement cost is high

Method used

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  • Measurement method and device for large-curvature-radius non-zero-digit interference based on virtual Newton's ring
  • Measurement method and device for large-curvature-radius non-zero-digit interference based on virtual Newton's ring
  • Measurement method and device for large-curvature-radius non-zero-digit interference based on virtual Newton's ring

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Embodiment

[0051] A Fizeau-type spherical radius of curvature non-zero position detection system was constructed. The measured part is a concave mirror with a standard value of curvature radius of 41400mm and an effective aperture of 50mm; the standard reference spherical curvature radius is 51000mm and an effective aperture of 50mm.

[0052] Step 1. Collect the Newton's ring interferogram T(x,y) of the spherical surface 7 to be measured.

[0053] Step 2. Detect the non-zero position of the radius of curvature of the spherical surface. The ZEMAX model simulates the standard spherical radius of curvature as R 0 The return error W_retrace of the standard Newton ring interferogram is substituted into the simulated wave surface data of the standard Newton ring interferogram, and the standard Newton ring interferogram T is obtained by simulation. 0 (x,y):

[0054] T 0 (x,y)=A 0 (x,y)+B 0 (x,y)cos[2πf 0 (x 2 +y 2 )]

[0055] A 0 (x, y) is the background light intensity of the standard...

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Abstract

The invention provides a measurement method and device for large-curvature-radius non-zero-digit interference based on a virtual Newton's ring. Circular carrier-frequency Newton's ring interferograms are converted into linear carrier-frequency interferograms via second-order polar coordinates, a low-frequency moire fringe graph after low-pass filtering is demodulated, wavefront differential data between a to-be-measured spherical surface and a standard spherical surface is extracted, and a calculation formula of the curvature radius is derived. On the basis of a model of a ZEMAX software based Fizeau spherical large-curvature-radium non-zero-digit detection system, a finite iteration method is used correct backhaul errors during Newton's ring interferogram collection in non-zero-digit detection. The Fizeau spherical large-curvature-radium non-zero-digit detection system is constructed, and verification for the spherical large-curvature-radium non-zero-digit measurement technology based on the virtual Newton's ring is completed.

Description

technical field [0001] The invention belongs to optical measurement technology, in particular to a large curvature radius non-zero position interference measurement method and device based on Newton's ring. Background technique [0002] Spherical mirror is a common optical element in optical system and has important applications in various optical systems. For example, in the next-generation lithography projection objective lens system (Extreme Ultra-violet, EUV for short), a 13.5nm total reflection lithography objective lens is used. The system contains 6 pieces of off-axis spherical or aspheric mirrors, and the processing quality of the spherical mirrors has a key influence on the imaging effect of the whole system. The radius of curvature (ROC) is an important parameter to characterize the optical properties of an optical spherical mirror. The radius of curvature of the spherical mirror has a great influence on the imaging quality of the optical system. During the proc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/255
CPCG01B11/255
Inventor 高志山黄磊杨忠明王凯亮赵彦陈玥洋
Owner NANJING UNIV OF SCI & TECH
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