Method for correcting deposition errors of broadband anti-reflection films prepared by quartz monitoring method

Abstract

The invention relates to a method for correcting deposition errors of broadband anti-reflection films prepared by a quartz monitoring method. The method comprises the following steps: 1) a monitoringthickness is designed; a four-layer film system is prepared; and the four-layer film system comprises two layers of films with two thicknesses and prepared by high-refractive-index materials, and twolayers of films with two thicknesses and prepared by low-refractive-index materials; 2) through reverse inversion and linear fit of the prepared four-layer film system, film thickness errors of the high-refractive-index materials and the low-refractive-index materials are obtained; and 3) film plating parameters of the broadband anti-reflection films to be prepared are corrected by the film thickness errors of the same materials. Compared with the prior art, the method can effectively correct the deposition errors and improve the spectral property, is simple in operation and high in generality, and achieves wide production of the broadband anti-reflection films in reality.

Description

technical field [0001] The invention relates to the field of optical thin films, in particular to a method for correcting deposition errors in the preparation of broadband anti-reflection films by the quartz monitoring method. Background technique [0002] With the rapid development of modern optical technology, the requirements for the related properties of optical films are also constantly increasing. In addition to low-loss films used in gravitational wave detection devices and high-power laser films in laser nuclear fusion devices, optical films with wider and more complex optical properties such as broadband anti-reflection coatings have also become the focus of attention. Usually, the broadband anti-reflection coating has many layers, and the thickness of each layer is not the same, and it contains a relatively thin layer, which brings great difficulties to the actual preparation of the film. The deposition error caused by the monitoring technology will seriously affe...

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Problems solved by technology

When the broadband anti-reflection coating is prepared by using the quartz monitoring method alone on the electron beam evaporation coating equipment, due to the limitation of the control accuracy of the method, there will be a large error in the actual thickness of the film layer, which will seriously affect the optical characteristics of the broadband anti-reflection coating. big impact

Moreover, the relative error of the film layer has a nonlinear relationship with its thickness. The smaller the film thickness, the larger the relative error, which has caused great difficulties for the accurate acquisition and correction of deposition errors.

[0004] The method of directly correcting the deposition error is to use the transmission electron microscope to directly obtain the thickness error of various film layers. The test accuracy is high and the result is reliable. However, this method has problems such as expensive test cost and damage to the surface of the sample during the test process.

The indirect method of correcting the deposition error is based on the reverse inversion method of the sample spectrum, but due to the nonlinear relationship between the relative error and the film thickness, and the problem of spectral ambiguity caused by the complex film system of the broadband anti-reflection film, these will seriously Affect the reliability of inverse inversion results, resulting in the inability to accurately obtain the real depositional errors

So far, there is no reliable, efficient, and non-destructive universal method that can accurately obtain and correct the deposition error of the broadband AR coating prepared by the quartz monitoring method

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