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Gao F.,CAS Academy of Opto Electronics | Gao F.,Beijing Excimer Laser Technology and Engineering Center | Gao F.,University of Chinese Academy of Sciences | Zhao J.,CAS Academy of Opto Electronics | And 7 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

In lithography, online spectral metrology of excimer laser lithographic light sources is used as the evaluation and monitoring the quality of the output laser lithography equipment, through the spectrum measurement we can know the running status of lithography equipment. Center wavelength and Full-Width-At-Half-Maximum(FWHM) are two important indicators of online spectral metrology. Traditional way of accurately measuring laser spectrum is to use a high resolution grating spectrometers. These instruments can provide accurate spectral measurement,but are very bulky and expensive. Fabry - Perot (FP) etalon is based on the principle of multi-beam interference, high spectral resolution can be done, is a modern high-resolution spectroscopy indispensable instrument. echelle has big blaze Angle, can achieve high The blazed order, realize high resolution(lower than etalon). This paper introduces a method of using Echelle and etalon, through the analysis of the diffraction line fringes of ArF laser and a series of algorithms to deal with data, realize the on-board measurement of center wavelength and FWHM. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Source


Lu Z.,CAS Academy of Opto Electronics | Lu Z.,Beijing Excimer Laser Technology and Engineering Center | Qi Y.,CAS Academy of Opto Electronics | Qi Y.,Beijing Excimer Laser Technology and Engineering Center | And 7 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Rapid inspection of a projection optics incorporated to 193 nm excimer-exposure system is important for 90 nm node and beyond IC manufacturing. To overcome the problems of the collimator lens presented in high NA high accuracy wavefront error metrology with Shack-Hartmann wavefront sensor, a pinhole array is used as the illumination source, which produces an array of high NA and high accuracy spherical waves, and form a high brightness source. In this paper, the diffraction of the pinhole array is calculated by using finite-difference time domain method and the theory of partial coherence. The distribution of the pinhole array considered here includes square, hexagonal and random distribution. The results shown that, pinhole diameter and separation in pinhole array have significant influence on the intensity contrast of the diffracted light, and the light intensity diffracted by the random pinhole array is smoother than that diffracted by the square or hexagonal distribution pinhole array, and is preferential in high precision wavefront error metrology. © 2015 SPIE. Source


Meng Q.,CAS Academy of Opto Electronics | Meng Q.,Beijing Excimer Laser Technology and Engineering Center | Meng Q.,University of Chinese Academy of Sciences | Qi Y.,CAS Academy of Opto Electronics | And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The centroid estimation, wavefront reconstruction and environment (typically temperature) are the main error sources of the Shack-Hartmann wavefront sensor (SHWS). In this paper, theoretical and experimental studies are conducted to analyze the effect of ambient temperature on the measurement accuracy of SHWS. The spot arrays corresponding to ambient temperature varied from 20.5 to 24 degrees are obtained by using the thermal analysis features in ZEMAX. The wavefronts are then reconstructed by home-made software from these spot arrays. By using the wavefront diffracted by a single mode optical fiber and the SHWS, the experiment setup is built to verify the results obtained by theoretical analysis. The results obtained by theoretical analysis and experiments are coincident well. The variation of the wavefronts measured by SHWS will be smaller than 0.06 nm RMS if the ambient temperature variation is controlled within 0.1 degree. The range of temperature within ±2 degrees, the max wavefront deviation is 2.12 nm. This research will be of guiding significance to ambient temperature control in high precision wavefront error metrology by using SHWS. © 2015 SPIE. Source


Lu Z.,CAS Academy of Opto Electronics | Lu Z.,Beijing Excimer Laser Technology and Engineering Center | Qi Y.,CAS Academy of Opto Electronics | Qi Y.,Beijing Excimer Laser Technology and Engineering Center | And 6 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2015

The uniform and high brightness illumination light is the key for testing the projection objective lens in deep ultraviolet region with nanometer accuracy by using the method of Shack-Hartmann wavefront sensor. The intensity contrast of the wavefront diffracted by the random arrangement pinhole array is optimized by using finitedifference time domain method and the theory of partial coherence. The wavefront diffracted by the pinhole array with random arrangement is smoother compared with that with periodic arrangement. Analyzing the wavefront diffracted by the single pinhole shows that the larger the pinhole diameter is, the bigger the intensity contrast of the wavefront will be. The intensity contrast of the wavefront diffracted by double pinholes reaches to maximum value when their separation is 74 nm. The calculation and analysis show that, to obtain the wavefront whose intensity contrast meets the requirement of nanometer accuracy wavefront error metrology, the diameters of the pinholes in pinhole array with random arrangement should be 170 nm and their separations should not be less than 306 nm. In this case, there are 428 pinholes in the pinhole array, and the intensity contrast of the wavefront diffracted by them is 11.70. ©, 2015, Chinese Optical Society. All right reserved. Source


Fan Y.,CAS Academy of Opto Electronics | Fan Y.,Beijing Excimer Laser Technology and Engineering Center | Zhou Y.,CAS Academy of Opto Electronics | Zhou Y.,Beijing Excimer Laser Technology and Engineering Center | And 10 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2016

ArF excimer lasers characterized by short wavelength and high photon energy have important applications in the field of integrated circuit lithography, material processing, laser medicine, and so on. Structure of the compound cavity 193 nm ArF excimer laser is designed based on the linewidth narrowing techniques. Principles of the compound cavity laser are theoretically analyzed. Based on the characteristics of long cavity length in excimer laser system, the solutions for achieving effective mode-locking in compound cavity are proposed and experimentally verified. The laser output with nearly the same linewidth as the narrow-band cavity with dispersive elements and 4.02 times large energy is obtained. The laser efficiency and the energy stability are greatly improved as well. © 2016, Chinese Laser Press. All right reserved. Source

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