Extraction of the Coefficient of Thermal Expansion of Thin Films from Buckled Membranes

1998 ◽  
Vol 546 ◽  
Author(s):  
V. Ziebartl ◽  
O. Paul ◽  
H. Baltes

AbstractWe report a new method to measure the temperature-dependent coefficient of thermal expansion α(T) of thin films. The method exploits the temperature dependent buckling of clamped square plates. This buckling was investigated numerically using an energy minimization method and finite element simulations. Both approaches show excellent agreement even far away from simple critical buckling. The numerical results were used to extract Cα(T) = α0+α1(T−T0 ) of PECVD silicon nitride between 20° and 140°C with α0 = (1.803±0.006)×10−6°C−1, α1 = (7.5±0.5)×10−9 °C−2, and T0 = 25°C.

1997 ◽  
Vol 505 ◽  
Author(s):  
G. Cornella ◽  
S. Lee ◽  
O. Kraft ◽  
W. D. Nix ◽  
J. C. Bravman

ABSTRACTX-ray strain analysis via Generalized Focusing Diffractometry (GFD) [1], and the concurrent need for accurate values of the unstrained lattice parameter, are discussed. A new method for determining the unstrained lattice parameter without knowledge of the elastic constants of the sample material is described. Stress measurements at varying temperatures, and extraction of the coefficient of thermal expansion from these measurements, are demonstrated for aluminum and gold films.


1999 ◽  
Vol 605 ◽  
Author(s):  
Melissa Bargmann ◽  
Amy Kumpel ◽  
Haruna Tada ◽  
Patricia Nieva ◽  
Paul Zavracky ◽  
...  

AbstractMicroelectromechanical systems (MEMS) have potential application in high temperature environments such as in thermal processing of microelectronics. The MEMS designs require an accurate knowledge of the temperature dependent thermomechanical properties of the materials. Techniques used at room temperature often cannot be used for high-temperature property measurements. MEMS test structures have been developed in conjunction with a novel imaging apparatus designed to measure either the modulus of elasticity or thermal expansion coefficient of thin films at high temperatures. The MEMS test structure is the common bi-layered cantilever beam which undergoes thermally induced deflection at high temperatures. An individual cantilever beam on the order of 100 νm long can be viewed up to approximately 800°C. With image analysis, the curvature of the beam can be determined; and then the difference in coefficient of thermal expansion between the two layers can be determined using numerical modeling. The results of studying silicon nitride films on silicon oxide are presented for a range of temperatures.


1998 ◽  
Vol 546 ◽  
Author(s):  
Patricia Nieva ◽  
Haruna Tada ◽  
Paul Zavracky ◽  
George Adams ◽  
Ioannis Miaoulis ◽  
...  

AbstractThe optimization of microelectronic devices and Microelectromechanical Systems (MEMS) technology depends on the knowledge of the mechanical and thermophysical properties of the thin film materials used to fabricate them. The thickness, stoichiometry, structure and thermal history can affect the properties of thin films causing their mechanical and thermophysical properties to diverge from bulk values. Moreover, it is known that the mechanical and thermophysical properties of thin films vary considerably at different temperatures. Bulk properties of semiconductors have been characterized over a wide range of temperatures; however there is limited information on thin film properties of silicon-based compounds such as silicon nitride, specially at high temperatures. In our work, MEMS devices designed to record the localized maximum temperature during high temperature thermal processes, which we call Breaking T-MEMS, will be presented as a way to determine some of the mechanical properties (Young's modulus and fracture strength) and thermophysical properties (coefficient of thermal expansion) of silicon-rich nitride thin films at high temperatures.The Breaking T-MEMS device consists of a thin film bridge suspended over a substrate. During testing, the devices are thermally loaded in tension by heating the sample. The low coefficient of thermal expansion of the film relative to that of the substrate causes the thin film bridge to break at a specific temperature. Through a combination of indirect experimental measurements, analytical expressions, numerical and statistical analysis, and if the experiments are conducted using at least two different substrates of known temperaturedependent coefficients of thermal expansion, some of the material properties of the film can be calculated from the breaking temperatures of various devices. The two candidate materials for the substrate are silicon and aluminum oxide (sapphire).


1992 ◽  
Vol 114 (4) ◽  
pp. 470-472 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Edward Jih ◽  
Bruce E. Artz ◽  
Larry W. Cathey

When modeling the thermomechanical behavior of electronic packages, engineers often need to include the temperature dependence of coefficients of thermal expansion (CTE) of materials involved in the finite element model. In ABAQUS some input parameters associated with such temperature dependent CTE are not clearly defined, and directions to determine the value of these parameters are not given. Misinterpretation of these variables can result in serious errors in the finite element result. This brief tends to illustrate in detail the implementation steps of the temperature dependent CTE in ABAQUS and presents an error analysis so that a quantitative measure of the error can be obtained. The information presented here is regarded critical to those who are using ABAQUS with temperature dependent CTE.


2006 ◽  
Vol 914 ◽  
Author(s):  
George Andrew Antonelli ◽  
Tran M. Phung ◽  
Clay D. Mortensen ◽  
David Johnson ◽  
Michael D. Goodner ◽  
...  

AbstractThe electrical and mechanical properties of low-k dielectric materials have received a great deal of attention in recent years; however, measurements of thermal properties such as the coefficient of thermal expansion remain minimal. This absence of data is due in part to the limited number of experimental techniques capable of measuring this parameter. Even when data does exist, it has generally not been collected on samples of a thickness relevant to current and future integrated processes. We present a procedure for using x-ray reflectivity to measure the coefficient of thermal expansion of sub-micron dielectric thin films. In particular, we elucidate the thin film mechanics required to extract this parameter for a supported film as opposed to a free-standing film. Results of measurements for a series of plasma-enhanced chemical vapor deposited and spin-on low-k dielectric thin films will be provided and compared.


2016 ◽  
Vol 18 (31) ◽  
pp. 21508-21517 ◽  
Author(s):  
Xiao-Ye Zhou ◽  
Bao-Ling Huang ◽  
Tong-Yi Zhang

Surfaces of nanomaterials play an essential role in size-dependent material properties.


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