White light interferometer with fast zero-setting system

Abstract

The invention discloses a white light interferometer with a fast zero-setting system. A light path of the white light interferometer is added with the following system, which is characterized in that: lasers emitted by a tunable laser are expanded by an expander and then merged to the light path through a third beam splitter and a first beam splitter which are installed behind a collimating system; a dichronic mirror totally reflecting long wave is arranged between a converging lens and a camera, one end of a detector receives reflective lights of the dichronic mirror and the other end thereof is connected with a computer via an AD / DA card. According to the invention, zero path difference setting of the white light interferometer can be realized by wavelength scanning laser interference measurement, and an angle of dip of a surface to be measured is obtained by analyzing the spacing of white light interference fringes in order to achieve automatic setting. Since the above procedures are free from operations with large data, the setting time of the white interference interferometer can be reduced to about 20 seconds, which dramatically improves the detection efficiency of the white interference interferometer. The white interference interferometer with the fast zero-setting system is especially suitable for those large-area surfaces or circumferential surfaces which require the measurement of various positions and need to be spliced.

Description

technical field [0001] The invention relates to an interferometer, in particular to a white light interferometer with a fast zeroing system. Background technique [0002] At present, ultra-precision components and materials such as MEMS devices, waveguide materials, semiconductor wafers, and thin-film technology are in a stage of rapid development. The output value of MEMS devices alone reached 5 billion US dollars in 2005, and it is rising at a rate of 20% per year. At the same time, it is becoming more and more important to quickly and accurately detect the surface of these devices to ensure the quality consistency of products. Vertical Scanning White Light Interferometer (hereinafter referred to as white light interferometer) is the most important of them. testing method. Existing white light interferometers already have a longitudinal measurement resolution as high as 0.01nm, and the measurement time can be as fast as several seconds, such as Taylor Hobson's CCI6000, Zy...

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Problems solved by technology

However, the measurement accuracy of this interferometer can only reach the sub-micron level, and there is still a certain gap between the 0.01nm longitudinal measurement resolution of the white light interferometer.

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