Two-way lighting differential confocal measurement device and method based on ellipsoid reflection

Abstract

The invention discloses a two-way lighting differential confocal measurement device and a two-way lighting differential confocal measurement method based on ellipsoid reflection, and belongs to an optical microscopic measurement technology. The device comprises a laser device, a collimation beam expander, a polarization spectroscope, a 1 / 4 wave plate, a focusing objective lens, a three-dimensional micro displacement objective table, a collection objective lens, a spectroscope, a first needle hole, a second needle hole, a first detector, a second detector and a two-way lighting system consisting of an ellipsoid reflector and a spherical reflector. The measurement method comprises the following steps of: detecting a group of confocal signals with equidistant focuses on an image side through the two detectors; processing the confocal signals through differential calculation or anti-interference calculation; and obtaining micro displacement information according to a differential confocal measurement response curve. According to the device and the method, the high-value aperture lighting and detection of which the value aperture is 1 is realized; and the device and the method have the characteristics of high axial resolution and favorability for improving the point scanning resolution and effectively suppressing confocal noise or series-mode noise and are particularly applicable to small-view-field, high-sensitivity and micro displacement measurement for points on a proximate-axis.

Description

technical field [0001] The invention belongs to optical microscopic measurement technology, and mainly relates to an ultra-precise measuring instrument for three-dimensional microstructure, microstep, microgroove line width, depth and surface shape measurement in microstructured optical elements, microstructured mechanical elements, and integrated circuit elements. Non-contact measuring method and device. Background technique [0002] Confocal scanning measurement is one of the important technical means to measure three-dimensional microstructure, microstep, microgroove line width, depth and surface shape in the fields of micro optics, micromechanics and microelectronics. However, traditional confocal technology has been restricted by traditional lens imaging. The principle limitation of numerical aperture less than 1. [0003] Differential confocal scanning measurement is one of the typical improved measurement methods. The differential confocal scanning measurement inclu...

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Problems solved by technology

However, the traditional double-pass illumination confocal technology is also difficult to further improve the measurement resolution of the system by increasing the numerical aperture.

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