Online projection objective wave aberration detection device and method

Abstract

The invention relates to an online projection objective wave aberration detection device and method. The detection device comprises a light source, a rotary scatterer, a first focusing lens, an optical fiber array, a second focusing lens, a scattering optical element, an object plane optical grating, an image plane optical grating, a two-dimensional photoelectric sensor, a phase-shift control module and a computer, wherein the rotary scatterer is composed of a support, an electric motor and a circular diffusion scattering optical element, and is combined with the multimode optical fiber array for converting a coherent light or partially coherent light source into incoherent light; ten interference fringe patterns with phase shifting amounts of 0, pi/6, pi/3, pi/2, 2pi/3, 5pi/6, pi, 5pi/3, 3pi/2 and 11pi/6 respectively are acquired to calculate a phase position and the influence of multilevel diffraction light interference of the optical grating on the phase position extraction precision is eliminated. The device and the method can improve the modulation effect of the object plane optical grating on the optical field spatial coherence so as to achieve a high-precision alignment effect, reduce the system error of phase position extraction in wave aberration detection and improve the wave aberration detection precision of an optical system.

Description

technical field [0001] The invention relates to a wave aberration detection device of an optical system, in particular to an online wave aberration detection device and method of a projection objective lens of a lithography machine illuminated by an expanded light source. Background technique [0002] Photolithography technology is one of the core technologies in the manufacture of very large-scale integrated circuits. The pattern on the mask is transferred to the photoresist coated on the surface of the silicon wafer by exposure method, and then the pattern is transferred by developing, etching and other processes. transferred to silicon wafers. The projection objective lens is the core component of the imaging system of the lithography machine. The wave aberration of the projection objective lens is the main factor leading to the deterioration of the lithography imaging quality, and ultimately leads to the decrease of the imaging contrast of the lithography machine, the na...

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Problems solved by technology

However, the problem with this device is that the light source is partially coherent light, which directly affects the modulation effect of the spatial coherence of the light field and thus affects the measurement accuracy.

U.S. Patent No. 7,333,216 discloses a wave aberration detection device that adopts a multimode fiber array to reduce the spatial coherence of the light source (refer to prior art [2], U.Wegmann, H.Haidner, M.Schriever.Apparatus for wavefront detection, United States patent US7333216B2,2008.), but the problem with this device is that there is no effective alignment and parallel adjustment function between the object plane grating and the image plane grating, and it is easy to introduce system errors

Matthieu Visser et al. proposed an extended light source interferometer for EUV lithography objective lens wave aberration detection (refer to prior art [3], Matthieu Visser, Martign K.Dekker, Petra Hegeman, et al., "Extended source interferometry for at-wavelength test of EUV-optics”, Emerging Lithographic Technologies Iii, Pts 1 and 2, 1999.3676: p.253-263), but the problem is that the interference between the higher order diffraction items and the 0th order has not been eliminated

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