Shear displacement speckle measurement method and device

Abstract

The invention discloses a shear displacement speckle measurement method which comprises the following steps: two laser beams are combined and projected to a rough surface to obtain scattered light; the direction of the scattered light is changed and the scattered light is split into two light beams after the scattered light passes through a half-transparent and half-reflecting mirror, wherein the first light beam respectively passes through a first lens and a first detector to obtain a polychromatic speckle pattern of the scattered light, the deflection pitch angle of a measured surface is obtained according to the polychromatic speckle pattern, the second light beam respectively passes through a filter, a second lens and a second detector to obtain a monochromatic speckle pattern of the scattered light, and the moving distance of the measured surface is obtained according to the monochromatic speckle pattern; and the moving distance is eliminated and the measured surface is deflected to obtain a shear displacement. The invention further discloses a shear displacement speckle measurement device.

Description

technical field [0001] The invention relates to the field of integrated circuit equipment manufacturing, in particular to a shear displacement speckle measurement method and device. Background technique [0002] In optical and photoelectric testing, accurate measurement of the detector position is a prerequisite for ensuring accuracy. The most commonly used non-contact method for accurate detection of small displacements is laser interferometry. This method changes the position of the measured object along the optical path by comparing the optical path difference between the measured optical path and its internal reference optical path. It has high measurement accuracy, but its structure is complex, expensive, and affected by factors such as temperature and air pressure, it has strict requirements on the environment and complicated operation. [0003] Speckle correlation method is another non-contact measurement method. This method is not as accurate as laser interferometer...

AI Technical Summary

Problems solved by technology

[0004] In the disclosed technology, as shown in the technical solutions disclosed in CN2391169, CN1275712 and CN1844844, the speckle correlation methods mainly used in the prior art include: femtosecond transmission laser speckle correlation method with high precision, rough template Reflected laser speckle correlation method, both of which calculate the displacement of the measured surface according to the correlation of speckle images before and after movement, and the accuracy can reach sub-pixel level, but the measurement accuracy is affected by the deflection of the measured object when it moves

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