Confocal Measurement Device Based on Ellipsoid Reflected Illumination

Abstract

The invention discloses an ellipsoid-based reflecting lighting confocal measuring device, belonging to an optics microtechnique. A collimation beam expander, a large numerical aperture focusing objective lens, a pinhole, a three-dimensional micrometric displacement objective table, a focusing objective lens, a detecting pinhole and a detector are arranged on a laser direct light path in sequence; an ellipsoid reflecting lens is configured on the laser direct light path and at a position between the focusing objective lens and the detecting pinhole; a remote focus of the ellipsoid reflecting lens is located on the pinhole; a near focus of the ellipsoid reflecting lens is located on a surface of a sample arranged on the three-dimensional micrometric displacement objective table. With the adoption of the ellipsoid-based reflecting lighting confocal measuring device, a defect that an axial resolution force in a traditional confocal measuring technology is limited by an objective lens numerical aperture is overcome, lighting to large numerical apertures is realized, so that a transverse resolution force and the axial resolution force of a system are greatly improved.

Description

technical field [0001] The invention belongs to the field of optical microscopic measurement, and mainly relates to an ultra-precise non-contact measuring device for measuring the surface topography of three-dimensional fine structures in microstructure industrial samples. Background technique [0002] Confocal scanning measurement is one of the important technical means to measure three-dimensional microstructure, micro-step, micro-groove line width, depth and surface shape in the fields of micro-optics, micro-mechanics and micro-electronics. Including differential confocal curvature radius measurement method and device (public number CN101526341), confocal microscope and its height measurement method (public number CN1392962), polychromatic super-resolution differential confocal measurement method and device (public number CN101182992) The axial resolution and lateral resolution of the confocal scanning measurement system using the traditional lens illumination structure a...

AI Technical Summary

Problems solved by technology

However, due to the existence of the diffraction limit, it is difficult for the previous confocal scanning system based on the lens structure to make a breakthrough in improving the detection resolution by increasing the numerical aperture.

[0003] The confocal measurement system using reflective illumination structure can better solve this problem, such as the parabolic reflective system that has been proposed for a period of time and has been developed: using the parabolic reflector to reflect the plane detection light can be placed on the focus of the object to be measured The object is illuminated with a large aperture, but in order to reduce the occlusion ratio of the stage blocking the light source, a large-aperture reflector is used, and it is very difficult to manufacture a large-aperture plane wave illumination source with a matching diameter on the basis of ensuring aberration

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