Chinese Journal of Lasers, Volume. 42, Issue 3, 308008(2015)
Study on Ronchi Shearing Interferometry for Wave-Front Aberration Measurement of Lithography Projection Lens
Ronchi shearing interferometry modulates the spatial coherence of light field with extended source. With the advantages of simple structure, common- path, null- fringe detection, and so on the Ronchi shearing interferometer can be used for in situ aberration measurement of lithography projection lens. Ronchi shearing interferometry for wave-front aberration measurement of lithography projection lens is studied. The interference model of Ronchi shearing interferometer is derived by theories of grating diffraction and spatial coherence. A tenstep phase-shifting algorithm is proposed to eliminate negative effects of unwanted interference from the high order diffraction light, which limits the accuracy of phase retrieval. The effects of the first ±9 orders interference on phase retrieval accuracy can be eliminated. The peak-valley (PV) value and root mean square (RMS) value of theoretical phase retrieval error are less than 0.0046 λ and 0.0019 λ respectively. The theoretical interference model and the phase retrieval algorithm are validated.
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Wu Feibin, Tang Feng, Wang Xiangzhao, Li Jie, Li Sikun. Study on Ronchi Shearing Interferometry for Wave-Front Aberration Measurement of Lithography Projection Lens[J]. Chinese Journal of Lasers, 2015, 42(3): 308008
Category: measurement and metrology
Received: Oct. 15, 2014
Accepted: --
Published Online: Feb. 3, 2015
The Author Email: Feibin Wu (feibinwu@163.com)