New Jersey Institute of Technology Digital Commons @ NJIT Dissertations Electronic Theses and Dissertations Fall 1996 Study of stress in microelectronic materials by photoelasticity Hancheng Liang New Jersey Institute of Technology Follow this and additional works at: https://digitalcommons.njit.edu/dissertations Part of the Electrical and Electronics Commons Recommended Citation Liang, Hancheng, "Study of stress in microelectronic materials by photoelasticity" (1996). Dissertations. 1017. https://digitalcommons.njit.edu/dissertations/1017 This Dissertation is brought to you for free and open access by the Electronic Theses and Dissertations at Digital Commons @ NJIT. It has been accepted for inclusion in Dissertations by an authorized administrator of Digital Commons @ NJIT. For more information, please contact [email protected]. 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Contact UMI directly to order. UMI A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 UMI Number: 9618582 Copyright 1996 by Liang, Hancheng All rights reserved. UMI Microform 9618582 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT STUDY OF STRESS IN MICROELECTRONIC MATERIALS BY PHOTOELASTICITY by Hancheng Liang The study of stress is playing an important role in microelectronic technology. In comparison with other techniques, the photoelasticity technique has the advantages of having high spatial resolution and high sensitivity. It can be used in qualitative observation in real-time and quantitative determination of stress distribution in the microelectronic materials and devices. This dissertation presents a systematic study of photoelastic stress analysis in microelectronic materials and devices, ranged from theoretical study to practical system setup, from measurement methods to their applications. At first, based on the detailed survey on the piezo-optic properties of the crystals used in microelectronics, we apply the stress-optic law of engineering mechanics to study the stress in crystals, such as silicon, gallium arsenide, and diamond. We, for the first time, derive the relationship between the stress ellipsoid and the refractive index ellipsoid, and, derive the matrix forms of piezo­ optic coefficient tensor for several commonly used coordinates. These theoretical results have laid a firm ground for the photoelastic stress analysis of microelectronic materials and devices. Second, based on exclusive experiments, we develop several effective methods of photoelastic analysis to determine the stress state in the samples. Some of them are successfully borrowed from the classic photoelastic mechanics, such as the Semarmont compensation which is used to determine the decimal fringe of the isochromatic line, and the shearing stress difference method which is used to separate two principal stresses and obtain the stress distribution of a sample. We also provide our origination to the photoelastic techniques, such as the three-direction observation method which is used to abstract the principal stresses from the secondary principal stresses; the Fourier analysis method and the intensity analysis method, both of which are especially suitable for precisely and automatically determining the principal stress distribution in a large area. Combining computer and digital image processing techniques with photoelastic techniques, we set up a photoelastic measurement system, which has the capability of qualitative observation of the photoelastic patterns and quantitative measurement of the stress distribution. We apply the photoelasticity principles and methods to investigate the stress state in microelectronic materials, including developing a series of feasible methods to measure the stress distribution of the microelectronic materials and devices, investigating the mechanisms of stress induction and stress change. For example, we investigate the stress distribution of a synthetic diamond substrate, study the stress induced during the typical impurity diffusion processes for manufacturing power diodes, and analyze the stress induced in the thin film/substrate structures. We also develop some models to explain the measurement results and provide theoretical discussions of the results. STUDY OF STRESS IN MICROELECTRONIC MATERIALS BY PHOTOELASTICITY by Hancheng Liang A Dissertation Submitted to the Faculty of New Jersey Institute of Technology Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Department of Electrical and Computer Engineering January 1996 Copyright © 1996 by Hancheng Liang ALL RIGHTS RESERVED APPROVAL PAGE STUDY OF STRESS IN MICROELECTRONIC MATERIALS BY PHOTOELASTICITY Hancheng Liang Dr. Ken K. Chin, Dissertation Adviser Date Professor of Physics, NJIT Dr. John C. Hensel, Committee Member Date Distinguished Research Professor of Physics, NJIT Dr. Robert B. Marcus, Committee Member Date Research Professor of Electrical and Computer Engineering, NJIT Dr. William N. Carr, Committee Member Date Professor of Electrical and Computer Engineering, NJIT Professor of Physics, NJIT Dr. Yun-Qing Shi, Committee Member Date Associate Professor of Electrical and Computer Engineering, NJIT BIOGRAPHICAL SKETCH Author: Hancheng Liang Degree: Doctor of Philosophy in Electrical Engineering Date: January 1996 Education: • Doctor of Philosophy in Electrical Engineering New Jersey Institute of Technology, Newark, New Jersey, 1996 • Master of Science in Applied Physics South China Institute of Technology, Guangzhou, P. R. China, 1985 • Diploma of Electrical Engineering South China Institute of Technology, Guangzhou, P. R. China, 1980 Major: Electrical Engineering Presentations and Publications: Hancheng Liang, Yongxiong Pan, Shounan Zhao, Ganming Qin, and K. Ken Chin, "Two-Dimensional State of Stress in a Silicon Wafer", J. Appl. Phys. 71 (1992): 2863-2870. Hancheng Liang, Shounan Zhao, and K. Ken Chin, "A New Method of Determining the Stress State in Microelectronic Materials", Measurement Science and Technology, 6 (1995): 1-4. Hancheng Liang, Shounan Zhao, Ganming Qin, and K. Ken Chin, "Thin Film- induced Stress in Substrate/Thin Film Structure", Procedings of the Fourth International Conference on Solid-State and Integrated-Circuit Technology, Publishing House of the Electronics Industry, Beijing (1995): 272-274. Hancheng Liang, Andrei Vescan, Erhard Kohn, and K. Ken Chin, "Measurement of Stress in a Synthetic Diamond Substrate by Using Photoelastic Method", The Sixth European Conference on Diamond, Diamond-Like and Related Materials, Barcelona, Spain, 1995. Also accepted for publication in Diamond and Related Materials. iv To my beloved family v ACKNOWLEDGMENT The author wishes to express his sincere gratitude to his advisor, Dr. Ken K. Chin, for his encouragement,