&lt;title&gt;Manufacturing and investigation of objective lens for ultrahigh resolution lithography facilities&lt;/title&gt;

The calibration of misalignment aberrations is a key issue in the testing of high-numerical-aperture spherical surfaces, and it is hard to separate the high-order aberrations introduced by misalignment from the measured data. The traditional calibration method is still applicable in the case of only wavefront tilt, but no longer effective in the existence of defocus. A calibration technique based on the wavefront difference is proposed to calibrate the misalignment aberrations in the presence of wavefront defocus, and it can be carried out without foreknowledge of the spherical surface under test. With the wavefront difference method, the calibration needs two separate measurements to separate the high-order aberrations. Both the computer simulation and experiments with the ZYGO interferometer have been carried out to validate the proposed calibration technique, with the accuracies better than 0.0005λ RMS and 0.0010λ RMS achieved, respectively. The proposed calibration method provides a feasible way to lower the requirement on the adjustment in the measurement, while retaining good accuracy.

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Point diffraction interferometer with adjustable fringe contrast for testing spherical surfaces

Wang

Yang

Chen

et al. 2011

Appl. Opt.

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A point diffraction interferometer (PDI) with adjustable fringe contrast is presented for the high-precision testing of spherical surfaces. The polarizing components are employed in the PDI to transform the polarization states of the test and reference beams, and a good fringe contrast can be realized by adjusting the relative intensities of interfering waves. The proposed system is compact and simple in structure, and it provides a feasible way for high-precision testing of spherical surfaces with low reflectivity. The theory of the interferometer is introduced in detail, along with the properties of optical components employed in the system, numerical analysis of systematic error, and the corresponding calibration procedure. Compared with the testing results of the ZYGO interferometer, a high accuracy with RMS value about 0.0025λ is achieved with the proposed interferometer. Finally, the error consideration in the experiment is discussed.

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<title>Manufacturing and investigation of objective lens for ultrahigh resolution lithography facilities</title>

Cited by 4 publications

References 47 publications

Micro- and Nanoelectronics

Micro- and Nanoelectronics

Misalignment aberrations calibration in testing of high-numerical-aperture spherical surfaces

Point diffraction interferometer with adjustable fringe contrast for testing spherical surfaces

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