Apparatus for measuring film thickness and refractive index in medium

A film thickness, internal measurement technology, applied in the field of optical measurement, to achieve the effect of improving measurement accuracy, strong practical value, and simple operation

Inactive Publication Date: 2014-04-30
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
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  • Claims
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Problems solved by technology

[0003] The purpose of the present invention is to solve the problem of measuring the film thickness and refractive index from the medium incident to the air, and propose a device for measuring film thickness and refractive index in the medium, using the resonance curve of the F-P cavity to measure the s and s in the medium The relative phase difference between p, and thus accurate measurement of film thickness and refractive index

Method used

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  • Apparatus for measuring film thickness and refractive index in medium
  • Apparatus for measuring film thickness and refractive index in medium
  • Apparatus for measuring film thickness and refractive index in medium

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Embodiment Construction

[0019] In order to further illustrate the advantages and purposes of the present invention, the content of the present invention will be further described below in conjunction with examples.

[0020] The device used for measuring the relative phase difference in the optically dense medium of the present invention is as figure 2 shown. image 3 An embodiment of this device for measuring relative phase difference in an optically dense medium is given.

[0021] In this embodiment, the first high-reflection film and the second high-reflection film plane are made of optical quartz glass with low transmission loss. figure 2 Among the three optical surfaces, the surface where point A is located is the folding surface and the input-output coupling surface, and the reflectivity of p-polarization and s-polarization is both 93%. The surfaces where points C and D are located constitute the reflective surfaces at both ends of the equivalent confocal F-P cavity, and its reflectivity is ...

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Abstract

The invention, which belongs to the technical field of optical measurement, relates to an apparatus for measuring a film thickness and a refractive index in a medium. After being emitted by a semiconductor diode is collimated by a non-aspheric surface collimating lens, light enters a diffraction grating by an incident way at a certain angle and is diffracted by the diffraction grating; the first-stage diffraction light is reflected back by the same route; the zero-stage diffraction light passes through a detachable optoisolator and a half wave plate and then enters an F-P cavity by an incident way to form optical feedbacking; the feedback light successively passes through a second PBS and a first PBS and then is detected by a PD detector; and the detected light is displayed by an oscilloscope to realize detection of the feedback light intensity and the spectral characteristic. According to the invention, a problem of measurement of the film thickness and refractive index in medium can be solved; and the measurement precision is substantially improved. Moreover, the apparatus can be operated simply and stably.

Description

technical field [0001] The invention relates to a device for measuring film thickness and refractive index in a medium, belonging to the technical field of optical measurement. Background technique [0002] When the light is reflected by the reflective film, the phases of the s component and the p component change. Usually the relative phase difference between the s and p components can be measured with an ellipsometer, such as figure 1 As shown, the light emitted by the LD is incident on the sample after passing through the polarizer, and its reflection is detected by the detector PD after passing through the analyzer. In this way, film thickness and refractive index can be further measured, but the measurement conditions of this type of ellipsometer limit the measurement from air incident to the medium, and the measurement accuracy of traditional ellipsometers is limited. As for the measurement of film thickness and refractive index from medium incident to air, there is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/06G01N21/21
Inventor 彭瑜
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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