Asymmetric-type phase shift grating marker and its uses in photo-etching machine objective lens aberration detection

Abstract

An asymmetrical phase-shifting grating mark and its application in the detection of object image aberration of a lithography machine. The mark is composed of two groups of asymmetrical phase-shifting gratings. The line directions of the two groups of gratings are respectively 90 degrees and 0 degrees. The mark is an alternating phase-shifting grating, and the phase difference between two adjacent light-transmitting regions in the grating is 180 degrees; the line-to-space ratio of the phase-shifting grating is 1:2, and the period of the phase-shifting grating is 1.92λ / NA, wherein, λ is the wavelength of the illumination source of the lithography machine, and NA is the average value of the maximum and minimum values ​​within the variable range of the numerical aperture of the projection objective lens of the lithography machine. The invention also provides an in-situ detection method for the wave aberration of the projected objective lens of the lithography machine based on the asymmetrical phase-shifting grating mark. By optimizing the structure and size of the phase-shifting grating, the aberration sensitivity of the test mark is significantly improved, and the detection accuracy is significantly improved by using the test mark to detect the wave aberration of the projection objective lens of the lithography machine.

Description

technical field [0001] The present invention relates to a lithography machine, in particular to an asymmetric phase-shifting grating mark and its application in the detection of object image aberrations of a lithography machine. Specifically, the present invention is an asymmetric phase-shifting grating mark and based on the In situ detection method for wave aberration of labeled lithography machine projection objectives. Background technique [0002] The lithography machine is the core equipment in the very large scale integrated circuit manufacturing process. The projection objective lens system is one of the most important subsystems of the lithography machine. The wave aberration of the projection objective will reduce the image quality of lithography and reduce the process window of lithography. During the imaging process of the projection objective lens, coma aberration causes the lateral position of the aerial image to shift, which increases the overlay error of the...

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Problems solved by technology

[0005] In the prior art 2, when measuring the wave aberration, the influence of the size of the phase-shift mask pattern and the line-to-space ratio on the aberration sensitivity was ignored, and only the method of phase shift was considered to improve the aberration sensitivity, which affected the wave aberration of the projection objective lens. Further improvement in detection accuracy

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