A Microstructure Topography Measurement Method and Device Based on Spectral Modulation Depth Code

Abstract

The invention discloses a method and device for measuring microstructure morphology based on spectral modulation depth coding. An element to be measured and a spatial light modulator are conjugated atthe center wavelength of the spectral range used in the measurement; a beam folding coupler, the spatial light modulator, a collimating and expanding lens, a beam splitter, an axial non-achromatic microscope objective lens, an imaging lens and a color camera are in a common optical path structure. During the measurement, the pre-calibration of the corresponding relation of the 'spectral-depth' isfirstly carried out on a system device, and each frame monochromatic shift-phase fringe pattern reflected by the element to be measured is acquired by a measuring device, so as to obtain the modulation depth distribution of each monochromatic light fringe pattern related to the surface shape of the element to be measured, and the coded image is obtained; the 'spectrum-modulation depth' relation curve of each point on the surface to be measured is determined by using Gaussian, quasi-Gaussian or spline model fitting, the depth information of each point on the surface to be measured is demodulated, and the fast and precise measurement of the microstructure topography of the three-dimensional topography distribution of the element to tested, without mechanical scanning or contact, is completed.

Description

technical field [0001] The invention relates to a measurement technology of microstructure topography, in particular to a measurement method and device for microstructure topography based on spectral modulation degree depth coding, belonging to the field of advanced manufacturing and detection technology. Background technique [0002] In important areas of the national economy such as semiconductor manufacturing, artificial intelligence, and aerospace, opto-electromechanical components such as silicon-based wafers, microelectromechanical systems (MEMS), and computer-generated holograms (Computer-generated Holography, CGH) have a wide range of applications. application. The surface of these components often has a complex (like) mirror microstructure formed by machining, laser / plasma etching, spray coating and other processes. Its shape distribution not only reflects the external characteristics of components, but also is closely related to internal characteristics such as ha...

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Problems solved by technology

As a result, the entire measurement time is long, and it is only suitable for the detection of static object surfaces, and is extremely sensitive to external airflow disturbances and vibrations during the scanning process, and the structure of the system is also relatively complicated and the cost is high

[0004] In contrast, as an incoherent optical detection technology, the 3D shape measurement method based on fringe modulation coding has the advantages of more flexible and controllable measurement process and a relatively simple system structure, but in order to obtain the Axial surface shape distribution, still needs to use PZT for axial scanning, also has the disadvantages of weak anti-interference ability, only suitable for static measurement, etc.

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