Multi-wave-length phase-shift interferometric method based on white-light interferometric color fringe processing

Abstract

The invention relates to a multi-wave-length phase-shift interferometric method based on white-light interferometric color fringe processing. The method comprises: a white-light interferometric testing system is initialized and a silicon wafer is selected as a measured object; a position of the measured object on a light path in a visual range is adjusted, the measured object is scanned vertically in a scanning range, an image is stored; Bayer inverse transformation is carried out on the image by using MATLAB software to obtain true color image information; central wavelengths of R, G, B channels of the color image are calculated and obtained; the position of the measured object on the light path is adjusted again and thus the measured object is located at a focus point, seven white-light interferometric color images at different phase positions are collected and stored, and phase information is solved accurately by using a seven-step phase shift method; and preliminary estimation of the object height is obtained by using an equivalent wavelength method and height information of the object is solved precisely by using a fringe level method, so that three-dimensional morphology information of the surface of the object is obtained. According to the invention, multi-wave-length phase-shift interferometry is realized by one-time measurement, so that the external environment influence on the measuring process is reduced and the measuring precision is improved.

Description

technical field [0001] The invention relates to a multi-wavelength phase-shifting interferometry method. In particular, it relates to a multi-wavelength phase-shifting interferometry method based on white light interference color fringe processing. Background technique [0002] White light interferometry technology is an important measurement method, which has the advantages of non-contact, fast measurement speed, large range, and high precision. It is widely used in the field of ultra-precision processing devices, MEMS components, biological cell tissue and other microstructure topography measurement fields. . White light interference uses white light with a wide spectrum as the lighting device, and the light of all wavelengths is incoherently superimposed by interference, and colored fringes appear in the field of view. Using the CCD color camera to obtain the three-dimensional information of the image, the information of the three channels R, G, and B can be obtained. ...

AI Technical Summary

Problems solved by technology

However, the traditional multi-wavelength phase-shifting interferometry requires multiple monochromatic light sources for illumination, which increases the complexity of the system and is expensive

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