Multilayer film thermal expansion coefficient extraction method

Abstract

The invention discloses a method for extracting the thermal expansion coefficient of a multilayer film. The method comprises the following steps: measuring the pull-in voltage of each equal-width multilayer double-end clamped beam at normal temperature; measuring the pull-in voltage of each unequal-width multilayer double-end clamped beam at the normal temperature; calculating the equivalent Youngmodulus and the initial residual stress of an ith layer of film; measuring the pull-in voltage of each equal-width multilayer double-end clamped beam at the temperature T, and calculating the residual stress of the ith layer of film at the temperature T; calculating the thermal expansion coefficient of each layer of film at the temperature T; measuring the pull-in voltage of each equal-width multilayer double-end clamped beam at different temperatures, and calculating the residual stress of the ith layer of film at different temperatures; and calculating the coefficient of thermal expansion of each layer of film at different temperatures. The method for extracting the thermal expansion coefficient of the multilayer film provided by the invention is simple and easy to implement, convenientto operate and low in cost, and the multilayer double-end clamped beam is simple in test structure and high in measurement speed.

Description

technical field [0001] The invention relates to the technical field of micro-electromechanical systems, in particular to a method for extracting thermal expansion coefficients of multilayer films. Background technique [0002] Micro-Electro-Mechanical System (MEMS, Micro-Electro-Mechanical System) is a cutting-edge research field developed on the basis of microelectronics technology. Among them, the testing technology of MEMS material parameters is the key to ensure the yield rate of MEMS processing line. With the development of MEMS industrialization, more and more layers of thin films are required for MEMS products. The research on multi-layer thin film material parameter testing technology is not only the market demand, but also the development direction of MEMS material parameter testing technology. The thermal expansion coefficient of the film material is an important material parameter. On the one hand, the thermal expansion coefficient mismatch between the film and th...

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Problems solved by technology

[0003] At present, most of the commonly used test methods for the thermal expansion coefficient of multilayer films use optical means to detect the out-of-plane deformation of the sample, which requires the use of expensive optical test equipment, and the test speed is slow

In the paper published by Hu Dongmei and others in the Journal of Semiconductors, 2008, 29 (10): 2018-2022, the electrical test structure of the thermal expansion coefficient of polysilicon thin films uses the pull-in effect of double-ended fixed beams to obtain the thermal expansion coefficient of polysilicon thin films, which can Realize low-cost and fast measurement, but this solution is only suitable for the thermal expansion coefficient test of single-layer polysilicon thin films, and cannot be directly applied to the extraction of thermal expansion coefficients of multi-layer thin films

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