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

Abstract

An asymmetric phase shifting grid marker and application thereof in photo-etching machine object lens optical aberration detection are disclosed. The maker is composed of two set of asymmetrical phase shifting grids. The line directions of the two set of grids are 90 deg and 0 deg respectively. The maker is an alternant phase shifting grid which has two adjacent light transparent regions with a phase aberration of 180 deg; ratio of the land to groove of the grid is 1:2, and the circle of the phase shifting grid is 1.92 lambda / NA, wherein lambda is wavelength of the photo-etching machine light source, NA is the average value of the maximum value and the minimum value in the photo-etching machine projection objective numerical aperture variety range. The invention also discloses a photo-etching machine object lens optical aberration detection method based on the asymmetric phase shifting grid marker. By optimizing configuration and size of the phase shifting grid, optical aberration sensitiveness of testing markers is improved remarkably. So that the detection precision is increased apparently when the photo-etching machine projection objective wave aberration is detected by using the testing marks.

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...

AI Technical Summary

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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