Compound shade ultra-distinguish differential confocal measurement method and device

Abstract

The invention discloses a compound color super resolution differential confocal measuring device and comprises a first super resolution differential confocal measuring device, a second super resolution differential confocal measuring device, a dichroic mirror, a partial color difference correction objective lens as well as a computer device. According to the chromatic dispersion characteristics that the focusing of optical beams with different wavelength produces an ideal translation of focusing surface, the device forms two partly overlapped linear measuring areas and achieves two linear measuring areas with the characteristics of double-polar tracking, and therefore, not only measuring range expands for nearly one times, but also cross tracking measurement of the measuring area is realized; according to the application requirement, unanimous or inconsistent transverse or axial scanning characteristics can be achieved respectively in the two linear measuring areas with independent modulation of a multi-super resolution filter, moreover, on the condition of remaining the advantages of the differential and super resolution differential confocal measuring technology, the invention expands the linear range of the measuring device significantly.

Description

technical field [0001] The invention belongs to the field of ultra-precision measurement, and is an ultra-precise non-contact measuring device for measuring three-dimensional microstructures, microsteps, microgroove line width, depth and surface shape in microstructured optical elements, microstructured mechanical elements, and integrated circuit elements. Measurement methods and devices. Background technique [0002] Confocal scanning measurement technology is one of the important technical means to measure three-dimensional micro-structure, micro-step, micro-groove line width, depth and surface shape in the fields of micro-optics, micro-mechanics and micro-electronics. Its basic idea was proposed by M.Minsky in 1957 and obtained a U.S. patent in 1961. Its basic technical idea is to suppress stray light by introducing a pinhole detector and generate axial tomography capabilities. The reason is that the measurement sensitivity of the axial response signal is not high near t...

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Problems solved by technology

Its basic idea was proposed by M.Minsky in 1957 and obtained a U.S. patent in 1961. Its basic technical idea is to suppress stray light by introducing a pinhole detector and generate axial tomography capabilities. The reason is that the measurement sensitivity of the axial response signal is not high near the quasi-focus area of ​​the measurement surface, so it is only suitable for defocus displacement measurement

[0006] Attached Figure 2 is a typical wavelength response curve of the above-mentioned system, as shown in the figure, its linear measurement range is AX, and the measurement origin is O1, that is, when the position of the measurement surface moves from A to position X, differential motion can be effectively performed Or super-resolution differential confocal measurement, however, in this system, the high axial measurement resolution obtained by using a large numerical aperture focusing objective lens is contradictory to the extension of the axial measurement range, that is, the higher the axial resolution , the smaller the linear measurement range, this relatively narrow linear measurement range is one of the main obstacles restricting the wider application of existing differential and super-resolution differential confocal measurement techniques

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