Laser interferometry for measuring the thickness of two-layer films

A. B. Fedortsov; D. G. Letenko; L. M. Tsentsiper

doi:10.1117/12.299570

1 January 1998 Laser interferometry for measuring the thickness of two-layer films

A. B. Fedortsov, D. G. Letenko, L. M. Tsentsiper

Proceedings Volume 3345, International Workshop on New Approaches to High-Tech Materials: Nondestructive Testing and Computer Simulations in Materials Science and Engineering; (1998) https://doi.org/10.1117/12.299570
Event: International Workshop on New Approaches to High Tech Materials: Nondestructive Testing and Computer Simulations in Materials Science and Engineering, 1997, St. Petersburg, Russian Federation

Abstract

We present the results of investigations of the technique based on the principles of laser interferometry for measuring the thickness of two-layers films. The actuality of this kind of measurements is a result of necessity to control the geometric parameters of such films in scientific research and industry. The method of measurement is based on the analyses of the dependence of reflection coefficient as a function of the incidence angle of the laser beam due to the interference. To measure such dependencies we had designed experimental setups, described in our articles. This apparatus gives an ability to make the measurements of dependence of reflection coefficient as a function of the incidence angle in the range of angles from 30 degree(s) to 60 degree(s). The temporal duration of a single measurement is less than 0.2 ms, the diameter of probing spot is 30 micrometers and illuminance is less than 1 mW/mm². Fast measurement of angle dependence allows to get many data points that give an ability to determinate the parameters of two-layers films with high fidelity and precision. The possibility to determinate film's parameters follows from the analysis of the character of theoretical dependencies of the reflection coefficient R as a function of thicknesses of two layers with the different incidence angle of the laser beam (theta) . It can be seen that the reflection coefficients considerable depend on the layers thicknesses and the incidence angle. It gives an ability to design a technique to ascertain the simple correspondence among the dependence R equals f((theta) ) and the parameters of the film layers. An efficiency of this method was experimentally tested. We performed a series of measurements using the semiconductor structures Si₃N₄/SiO₂/Si having different thicknesses of the films Si₃N₄ and SiO₂, produced by the concern `Integral' (Minsk). The analysis of experimental and theoretical results shows that the described techniques can be applied for measuring the parameters of the multi-layers structures.

Citation Download Citation

A. B. Fedortsov, D. G. Letenko, and L. M. Tsentsiper "Laser interferometry for measuring the thickness of two-layer films", Proc. SPIE 3345, International Workshop on New Approaches to High-Tech Materials: Nondestructive Testing and Computer Simulations in Materials Science and Engineering, (1 January 1998); https://doi.org/10.1117/12.299570

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
6 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Reflection

Silicon

Electromagnetic radiation

Refractive index

Manufacturing

Semiconductors

Laser interferometry

Show All Keywords

Keywords/Phrases

Search In:

Publication Years