Quantitative Characterization of Sapphire and Silicon Nitride for Space Applications Circuit Subassemblies Using Cryogenic Cycling

2019 ◽  
Author(s):  
Kirsten Lovelace ◽  
Sonya Smith
Keyword(s):  
Thermal Expansion ◽  
Silicon Nitride ◽  
Electronic Device ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Design ◽  
Space Applications ◽  
Property Data ◽  
Engineered Systems ◽  
Α Al2o3

Abstract This research investigates the effects of thermal cycling from room to cryogenic temperatures (300K–4K) on the thermal expansion coefficient of two ceramic substrates of Silicon Nitride (Si3N4) and alpha-Alumina/Sapphire (α-Al2O3). Due to the shortage of available data, a comparative study with reference materials, Copper, AISI Carbon Steel 1008 and Molybdenum, are compared to the National Institute of Standards and Technology (NIST) property data as a proof of concept. Accurate thermal contraction data of materials at low temperatures are important in material selection and thermal design of engineered systems, such as, space electronic devices. Thermal expansion mismatch causes substantial problems in space electronic device reliability because of the various stresses imposed on the joint materials undergoing extreme thermal cycles. Theory supports the advantage of utilizing Sapphire (Al2O3) and Silicon Nitride (Si3N4) within microchip configuration. However, there is limited data available that confidently supports this assertion beyond theory. An electro-mechanical method for in-situ strain measurements is presented as a tool to characterize thermomechanical behavior of Sapphire and Silicon Nitride at temperatures below 50 K. The calculated coefficient of thermal expansion for silicon nitride is 1.35 · 10−6 1/K and 0.994 · 10−6 1/K for sapphire at 5.7 K. The results from this validation have a mean error percentage of less than 6 %.

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

1998 ◽  
Vol 546 ◽  
Author(s):  
V. Ziebartl ◽  
O. Paul ◽  
H. Baltes
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
Excellent Agreement ◽  
Energy Minimization ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Dependent ◽  
Minimization Method ◽  
Energy Minimization Method

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.

Bilayer graded Al/B4C/rice husk ash composite: Wettability behavior, thermo-mechanical, and electrical properties

2018 ◽  
Vol 52 (27) ◽  
pp. 3745-3758 ◽  
Author(s):  
Amin Bahrami ◽  
Niloofar Soltani ◽  
Martin I Pech-Canul ◽  
Shaghayegh Soltani ◽  
Luis A González ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Aluminum Alloys ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Expansion Coefficients ◽  
One Step ◽  
The Difference

In this study, wettability behavior of B4C substrate as well as B4C/crystalline rice husk ash and B4C/amorphous rice husk ash substrates with two aluminum alloys were studied. The electrical resistivity, thermal expansion coefficients, and thermal diffusivity of bilayer Al/B4C/rice husk ash composite fabricated by one-step pressureless infiltration were measured and the obtained data were systemically analyzed using the Taguchi method and analysis of variance. Boron carbide substrates after addition of amorphous or crystalline rice husk ash display good wettability with molten aluminum alloys. The results show that, electrical resistivity of Al/B4C/rice husk ash composites is mainly influenced by initial preform porosity, while the coefficient of thermal expansion of composites is determined by the chemical composition of infiltrated alloys. The measured values for coefficient of thermal expansion (10.5 × 10−6/℃) and electrical resistivity (0.60 × 10−5 Ω.m) of Al/B4C/rice husk ash composites, fabricated according to analysis of variance's optimal conditions are in good agreement with those of the projected values (11.02 × 10−6/℃ and 0.65 × 10−5 Ω.m, respectively). The difference between the corresponding values obtained from verification tests and projected values, for electrical resistivity and coefficient of thermal expansion are less than 5%. Finally, as a material selection approach, the strengths and weaknesses of the composites have been graphed in the form of radar diagrams.

Bi-Material Re-Entrant Triangle Cellular Structures Incorporating Tailorable Thermal Expansion and Tunable Poisson's Ratio1

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Xiaobing He ◽  
Jingjun Yu ◽  
Yan Xie
Keyword(s):  
Thermal Expansion ◽  
Cellular Structure ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Planar Lattice ◽  
Lattice Cell ◽  
Thermoelasticity Equation ◽  
Triangle Lattice ◽  
Temperature Load ◽  
The Relationship

Abstract Based on the bi-material triangle lattice cell, a new cellular structure, bi-material re-entrant triangle (BRT) cellular structure, is devised to incorporate tailorable coefficient of thermal expansion (CTE) and tunable Poisson's ratio (PR) properties by replacing the straight base of a triangle with two hypotenuse members. A general thermoelasticity equation to systematically build the relationship among the external force, the temperature load, and the deformation for planar lattice structures with bounded joints is derived and then embedded into a theoretical model for the devised BRT structure. Using assembled thermoelasticity equation, effective PR, Young's modulus, as well as CTE are computed. In order to guide designers to construct initial concepts, the design domain for coupling negative CTE and negative PR properties is plotted. The material-property-combination region that can be achieved by this cellular structure is determined within an Ashby material selection chart of CTE versus PR. Nine available combinations of CTE and PR properties are extracted and demonstrated with abaqus simulation.

Developments for Copper-Graphite Composite Thermal Cores for PCBs for High-Reliability and High-Temperature RF Systems

2016 ◽  
Vol 2016 (HiTEC) ◽  
pp. 000073-000078
Author(s):  
David L. Saums ◽  
Robert A. Hay
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Thermal Expansion ◽  
Thermal Design ◽  
High Heat Flux ◽  
Space Applications ◽  
Graphite Composite ◽  
Printed Circuit ◽  
Bulk Thermal Conductivity

Summary System designs that have only conduction cooling available, that must operate in harsh or challenging environments, present significant challenges to the system thermal engineer. A second thermal design challenge is continued miniaturization of semiconductor devices and increased functionality per square centimeter of semiconductor die, resulting in continued increases in device heat flux. Elimination of packaging materials allows more efficient heat transfer as thermal resistances from one material to another are reduced or designed out. When possible, concurrent elimination of package materials that have low bulk thermal conductivity and replacement with high thermal conductivity materials will improve heat transfer efficiency. Attachment of the resulting unpackaged semiconductor device can then be made directly to the circuit carrier; however, care must be taken regarding increases in potential for damage or failure due to mismatched coefficient of thermal expansion (CTE). Continuing reductions in die size that result in higher heat flux exacerbate this potential failure mechanism at the die-to-substrate level. This is further worsened in harsh environment (i.e., vibration, shock, high moisture, rapid power cycling) and/or high operating temperature conditions. For aerospace, military, geothermal, and other applications where increasingly high heat flux radio frequency (RF), microwave, and processor semiconductors are attached directly (with solders, silver sintering pastes, or other joining materials) to an organic or ceramic printed circuit card, efficient and rapid heat transfer becomes critical. These are frequently also applications where forced convection (air or liquid) may be unavailable to the system design engineer. One solution for thermal management design problems of this type has traditionally been the incorporation of one or more heavy copper layers within a complex multilayer printed circuit board (PCB). This solution, however, has come under increasing scrutiny in recent years due to concerns for weight (especially in airborne and space applications) and the potential for severe CTE mismatch between semiconductor die materials with relatively low thermal expansion values and the relatively very high value of copper. Therefore, development of CTE-matched alternative materials to replace a heavy copper layer has been a focus for development activities. A suitable selection must, however, have a bulk thermal conductivity that is as close to that of copper as is practicable. Recent developments of a copper-graphite composite material in sheet form that can be employed in standardized PCB manufacturing processes are described in this presentation.

Fabrication of Dental Ceramics from Silicon Nitride Core with Borosilicate Glass Veneer

2012 ◽  
Vol 506 ◽  
pp. 493-496
Author(s):  
Thanakorn Wasanapiarnpong ◽  
N. Cherdtham ◽  
P. Padipatvuthikul ◽  
C. Mongkolkachit ◽  
R. Wananuruksawong ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Silicon Nitride ◽  
Borosilicate Glass ◽  
Coefficient Of Thermal Expansion ◽  
Dental Materials ◽  
High Fracture Toughness ◽  
Dental Ceramics ◽  
Periodontal Ligament Fibroblasts ◽  
High Fracture ◽  
Human Teeth

Silicon nitride ceramic is a potential material for clinical indications due to its high fracture toughness, strength, and non-cytotoxicity. For this reason, Si3N4 ceramic is interested to apply for dental core. The superiority of Si3N4 ceramic is the low coefficient of thermal expansion (CTE) which is lower than that of zirconia and alumina ceramics that are popular in this field. In this study, borosilicate glass powder with 5 wt% of zirconia addition was prepared by melting at 1450 °C for 1 h. The glass melt was quenched and was then ground to be a powder and mixed with polyvinyl alcohol solution to be a paste. The Si3N4 specimens coated with the veneer were fired in electrical tubular furnace at 1100 °C for 15 min. The appearance of these specimens shows smooth, glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.05x10-6 °C-1 and the Vickers hardness as 4.0 GPa which is close to the human teeth. The specimens were tested by human gingival and periodontal ligament fibroblasts (HGF and HPDLF) and cytotoxicity by MTT assay. The results indicated that Si3N4 ceramic and borosilicate glass can be used as dental materials.

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 ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Silicon Nitride ◽  
Cantilever Beam ◽  
High Temperatures ◽  
Microelectromechanical Systems ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Dependent ◽  
Temperature Property ◽  
Silicon Nitride Films

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.

Interfacial Stresses in a Tri-Material Assembly Subjected to Differential Temperatures in the Layers in Electronic Packaging

2005 ◽  
Vol 2 (3) ◽  
pp. 162-170 ◽  
Author(s):  
D. Sujan ◽  
M. V. V. Murthy ◽  
K. N. Seetharamu ◽  
A. Y. Hassan
Keyword(s):  
Thermal Expansion ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Stress Model ◽  
Shearing Stress ◽  
Uniform Temperature ◽  
Die Attach ◽  
Proper Design ◽  
Two Parameters ◽  
Two Temperature

Schmidt's trimaterial model for shearing stress for uniform temperature is upgraded to account for differential temperatures in the layers. Subsequently a model for peeling stress is proposed from the consideration of moment equilibrium combined with the above mentioned upgraded shear stress model. The results are presented in terms of two parameters m1 and m2, relating the two temperature ratios at die-die attach interface and at die attach-substrate interface respectively. The results are also presented in terms of another two parameters n1 and n2, representing coefficient of thermal expansion ratios between die and die attach materials and die attach and substrate materials respectively. The obtained results can be useful resources in future analysis of trimaterial assemblies for proper design and material selection.

Mechanical and Thermophysical Properties of Silicon Nitride Thin Films at High Temperatures Using In-Situ Mems Temperature Sensors

1998 ◽  
Vol 546 ◽  
Author(s):  
Patricia Nieva ◽  
Haruna Tada ◽  
Paul Zavracky ◽  
George Adams ◽  
Ioannis Miaoulis ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
High Temperatures ◽  
Thermophysical Properties ◽  
Microelectromechanical Systems ◽  
Coefficient Of Thermal Expansion ◽  
Maximum Temperature ◽  
Wide Range

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).

scholarly journals Material Selection for Interfacial Bond Layer in Electronic Packaging

2018 ◽  
Vol 202 ◽  
pp. 01005
Author(s):  
D. Sujan ◽  
L. Vincent ◽  
Y. W. Pok
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Layer Thickness ◽  
Electronic Packaging ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Mismatch ◽  
Interfacial Stresses ◽  
Bond Layer ◽  
Two Parameters

In electronic packaging, typically two or more thin dissimilar plates or layers are bonded together by an extremely thin adhesive bond layer. Electronic assemblies are usually operated under high power conditions which predictably produces a high temperature environment in the electronic devices. Therefore, thermal mismatch shear and peeling stress inevitably arise at the interfaces of the bonded dissimilar materials due to differences in Coefficient of Thermal Expansion (CTE) typically during the high temperature change in the bond process. As a result, delamination failure may occur during manufacturing, machining, and field use. As such, these thermo-mechanical stresses play a very significant role in the design and reliability of the electronic packaging assembly. Consequently, critical investigations of interfacial stresses under variable load conditions in composite structure can result in a better design of electronic packaging with higher reliability and minimize or eliminate the risk of functional failure. In order to formulize bond material selection, analytical studies are carried out in order to study the influence of bond layer parameters on interfacial thermal stresses of a given package. These parameters include Coefficient of thermal expansion (CTE), poison’s ratio, temperature, thickness, and stiffness (compliant and stiff) of the bond layer. From the study, stiffness and bond layer thickness are identified as the key parameters influencing interfacial shearing and peeling stresses. The other parameters namely CTE, poisons ratio has shown insignificant influence on interfacial stresses due to the very thin section of bond layer compared to the top and bottom layers. The results also show that the interfacial stresses increases proportionally with the increase of temperature in the layers. Therefore, it is very important that the temperature is maintained as low as possible during the chip manufacturing and operating stages. Since only two parameters namely stiffness and bond layer thickness are identified as the key parameters, the interface thermal mismatch stresses can be reduced or eliminated by controlling these two parameters only. Therefore the identification of suitable bond layer parameters selection with reasonable accuracy is possible even without performing optimization process. Finally, this paper proposes a Metal Matrix Composite (MMC) bond material selection approach using rule of mixture material design. The outcome of this research can be seen in the forms of practical and beneficial tools for interfacial stress evaluation and physical design and fabrication of layered assemblies. The Engineers can utilize this research outcome in conjunction with guidelines for electronic packaging under variable thermal properties of layered composites.

Sign in / Sign up

Export Citation Format

Share Document