Temperature-Dependent Coefficient of Thermal Expansion of Silicon Nitride Films Used in Microelectromechanical Systems

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).


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.


2009 ◽  
Vol 6 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Joe Kuczynski ◽  
Silvio Bertling

The z-axis coefficient of thermal expansion (CTE) of a high-temperature laminate is dependent on sample construction. Reproducibility of the temperature-dependent CTE is significantly greater for thicker sample constructions. The CTE below Tg is independent of sample construction whereas the CTE above Tg depends on sample construction and increases with resin content. Temperature-dependent z-axis CTE is independent of heating rate but exhibited a marked dependence on the type of glass cloth used in the sample construction.


1998 ◽  
Vol 546 ◽  
Author(s):  
H. Tada ◽  
P. Nieva ◽  
P. Zavracky ◽  
I.N. Miaoulis ◽  
P.Y. Wong

AbstractHigh-temperature applications of microelectromechanical systems (MEMS), especially in new temperature sensor designs, require an accurate knowledge of the temperature-dependent thermophysical properties of the materials. Although the measurement of the mechanical properties of materials at room temperature has been widely conducted, the same techniques often cannot be used for high-temperature property measurements. In this study, a new technique was developed to find the thermal expansion coefficient of thin films at high temperatures. Bilayered cantilever beams undergo thermally induced deflection at high temperatures, which can be measured and correlated to material properties. An imaging system was developed for the experimental measurement of the beam curvature for temperatures up to 1000°C. To find the high-temperature property of thin films, a bilayered beam, consisting of polycrystalline silicon and silicon dioxide, was designed such that the change in the property of SiO2 had little effect on the curvature of the beam. Furthermore, numerical analysis showed that the Young's modulus of Si also had negligible effect on the curvature. Therefore, the analytical model for beam curvature was simplified to be only a function of the thermal expansion coefficient of Si layer. Using this model, the thermal expansion coefficient of polycrystalline Si film was determined for temperature range between room temperature and 1000°C. The method can be easily modified to find the Young's modulus of Si, as well as properties of SiO2.


Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..


Alloy Digest ◽  
1971 ◽  
Vol 20 (1) ◽  

Abstract UNISPAN LR35 offers the lowest coefficient of thermal expansion of any alloy now available. It is a low residual modification of UNISPAN 36 for fully achieving the demanding operational level of precision equipment. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and surface treatment. Filing Code: Fe-46. Producer or source: Cyclops Corporation.


Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.


Alloy Digest ◽  
1990 ◽  
Vol 39 (7) ◽  

Abstract AA 4032 has a comparatively low coefficient of thermal expansion and good forgeability. The alloy takes on an attractive dark gray appearance when anodized which may be desirable in architectural applications. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-305. Producer or source: Various aluminum companies.


2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000052-000057 ◽  
Author(s):  
Liang-Yu Chen

Aluminum nitride (AlN) has been proposed as a packaging substrate material for reliable high temperature electronics operating in a wide temperature range. However, it was discovered in a recent study that the dielectric properties of some commercial polycrystalline AlN materials change quite significantly with temperature at high temperatures. These material properties resulted in undesired large and temperature-dependent parasitic parameters for a prototype chip-level package based on an AlN substrate with the yttrium oxide dopant. This paper reports a method using a coating layer of a commercial thick-film glass on the AlN substrate surface to significantly reduce both the parasitic capacitances and parasitic conductances between neighboring inputs/outputs (I/Os) of a prototype AlN chip-level package. The parasitic parameters of 8-I/Os low power chip-level packages with the insulating glass coating were characterized at frequencies from 120 Hz to 1 MHz between room temperature and 500°C. These results were compared with the parameters of AlN packages without the glass coating. The results indicate that the parasitic capacitances and conductances between I/Os of the improved prototype AlN packages are significantly reduced and stable at high temperatures. The method using a glass coating provides a feasible way to mitigate the temperature dependence of dielectric properties of AlN and further utilize AlN as a reliable packaging substrate material for high temperature applications.


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