White light microscopic interference morphology reconstruction method based on mixing interference fringe

Abstract

The present invention provides a white light microscopic interference morphology reconstruction method based on a mixing interference fringe. A Mirau-type white light interferometry optical system is employed, a piezoelectric ceramics mobile station is employed to perform precision control of the vertical scanning movement of an interference objective, and a series of collected white light microscopy interferograms are stored. The collected interference grey-scale map is converted to a light intensity graph, a normalization modulation degree graph corresponding to a single-frame interference image is obtained through the frequency domain filtering and the base frequency signal extraction algorithm, and aiming at each independent vertical scanning position, a mixing interference image is obtained through the multiple of the same pixel point light intensity value and the corresponding modulation degree numerical value. A series of mixing interference images are obtained through vertical scanning, and the height information of each pixel point of a detected object is obtained through searching the mixing interference extreme value and the corresponding scanning displacement thereof to realize the three-dimensional morphology reconstruction of the object. The white light microscopic interference morphology reconstruction method based on the mixing interference fringe is high in measurement precision, high in anti-interference capability and simple in system, and is suitable for three-dimensional morphology detection of the micro-nano structure.

Description

technical field [0001] The invention belongs to the field of optical detection, and in particular relates to a white light micro-interference shape reconstruction method based on mixed interference fringes. Background technique [0002] Micro-nanostructures refer to functional structures with characteristic sizes ranging from micrometers to nanometers. They are widely used in microelectronics, aerospace, chemical pharmaceuticals, biotechnology and other fields, and are of great significance to promoting technological, economic and social development in the information age. With the continuous expansion of the application range of micro-nano devices, high-precision three-dimensional shape detection has become an important development goal of micro-nano detection technology. At present, the measurement methods are mainly divided into two categories: non-optical and optical. In non-optical inspection, there are mainly methods such as proslometry, atomic force microscope, and s...

AI Technical Summary

Problems solved by technology

[0003] Dong Chen and Joanna Schmit and others realized the search for the light intensity extremum point by adding an additional interferometer, and reduced the influence of external vibration and light source instability factors through real-time algorithm analysis. Although there is a certain effect, the processing speed is not only slow , but also increases the system complexity and detection cost

U.Paul Kumar's team proposed a three-wavelength absolute phase analysis method to determine the zero-order interference fringe through the phase. This method can effectively complete the detection when the object structure is continuous, but it cannot be widely used because it contains 2π phase ambiguity.

In short, in some current methods, the light intensity of the interferogram is unstable, and it is greatly affected by external disturbances, which leads to 3D shape measurement errors.

[0004] Due to the lack of measurement stability in the current three-dimensional shape recovery methods of micro-nano structures at home and abroad, they are seriously affected by external interference.

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