Method and apparatus for measuring thin film non-uniform stress on line

Abstract

The invention discloses an online measuring method and an online measuring device of uneven film strain, which belong to the technical fields of engineering materials, structural deformation and mechanic experiments. The online measuring device comprises a laser, a bean expanding device, a loading platform of test samples, gratings, an imaging system, a CCD camera and a computer that contains a computer program. The online measuring device uses the two gratings for implementing shearing interference of light beams that are reflected by a test sample surface, and interference strips are obtained; the computer program is used for processing the interference strips, extracting a central line of the interference strips and consequently calculating level change gradient of the interference strips, and full-scale curvature of the test sample surface is obtained; the uneven film strain is obtained by measuring the obtained curvature with a computational formula of the uneven film strain. The method and the device of the invention have compact structure and can realize full-scale, on-line and real-time measurement to the curvature as well as the measurement of the uneven film strain.

Description

technical field [0001] The invention relates to an experimental method and an experimental device for obtaining non-uniform stress in a film by measuring the curvature of a film-matrix system, and belongs to the technical fields of engineering materials, structural deformation and mechanical experiments. Background technique [0002] With the development of the electronics industry, the application of thin film materials is becoming more and more extensive, especially in the field of microelectronics, the unique advantages of thin film materials are more prominent. For the film-substrate system, residual stress will be introduced during processing, which will seriously affect the usability and reliability of the film. Therefore, it is of great significance to realize the online, real-time, and full-field measurement of the stress in the film. [0003] The current experimental method for measuring film stress is mainly to obtain film stress by measuring the curvature of the f...

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Problems solved by technology

Shull et al. (Shull, A.L. and Spaepen, F..Measurements of Stress during Vapor Deposition of Copper and Silver Thin Films and Multilayers, Journal of Applied Physics, Vol.80(1996), 6243-6256) studied the scanning laser method, which The limitation of this method is that it cannot realize the full field of curvature and it will take a lot of time when the scanning area is large. In addition, this method is also sensitive to vibration.

Finot et al. (Finot, M., Blech, I.A., Suresh, S. and Fujimoto, H.. Large Deformation and Geometric Instability of Substrates with Thin-film Deposits, Journal of Applied Physics, Vol.81(1997), 3457-3464) The grating reflection method was studied, which also does not allow full-field measurement of curvature

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