Diamond Heat Sinks For High Temperature Electronics: Simuilation, And Thermal Analysis

1995 ◽  
Vol 416 ◽  
Author(s):  
Nickolaos Strifas ◽  
Aris Christou
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
High Temperature ◽  
Thermal Resistance ◽  
Substrate Material ◽  
Heat Sinks ◽  
Substrate Thickness ◽  
High Temperature Electronics ◽  
Die Attach ◽  
Heat Sink Design

ABSTRACTperformance that can be achieved by utilizing a diamond heat - sink design which minimizes junction - to - case thermal resistance. Effects of the thermal conductivity of the substrate material, the thermal conductivity of the die attach material, the substrate thickness, and the die attach thickness onl Ihe thermal resistance are addressed. The results indicate that the temperature increase could be 3 to 4 times less with diamond heat-sinks when compared to other materials.

High-Temperature Transient Thermal Analysis for SiC Power Modules

2016 ◽  
Vol 858 ◽  
pp. 1078-1081 ◽  
Author(s):  
Fumiki Kato ◽  
Hiroshi Nakagawa ◽  
Hiroshi Yamaguchi ◽  
Hiroshi Sato
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
High Temperature ◽  
Thermal Resistance ◽  
Junction Temperature ◽  
Stable Operation ◽  
Transient Thermal Analysis ◽  
Die Attach ◽  
Power Modules ◽  
Transient Thermal

Transient thermal analysis is a very useful tool for thermal evaluation to realize the stable operation of SiC power modules which are operated at higher temperatures than conventional Si power modules. A transient thermal analysis system to investigate the thermal characteristics of SiC power modules at high temperature is presented. We have found that precise temperature measurement at the initial stage of the junction temperature decay curve is necessary in order to evaluate the thermal resistance and heat capacity of the die attach, since the thermal diffusivity of SiC is larger than that of Si and the temperature distribution of SiC die was considered. Using the proposed transient thermal analysis method, the thermal resistance and heat capacity of the AuGe die attach under the SiC-SBD was successfully evaluated at temperatures up to 250 °C.

Characterisation of test vehicle for in-situ measurement of die attach thermal conductivity

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000030-000034
Author(s):  
Conor Slater ◽  
Fabrizio Vecchio ◽  
Thomas Maeder ◽  
Peter Ryser
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Conductivity Measurement ◽  
Fatigue Cracking ◽  
Great Promise ◽  
Electronic Systems ◽  
Test Vehicle ◽  
High Temperature Electronics ◽  
Die Attach ◽  
Realistic Information

The continuing trend in the automotive and aviation industries to reduce complexity of electronic systems by removing cooling results in a need for high temperature electronics and associated packaging technologies. To ensure reliability over long periods of time the degradation of the packaging materials should be characterised. Epoxies show great promise as a reliable die attach solution for high temperature electronics due to their high bond strength, resistance to fatigue and chemical stability at temperatures up to 250°C. This work presents a method and test vehicle for measuring the thermal conductivity of an epoxy die attach. The test vehicle is constructed by using the epoxy under test to bond a die with an integrated PTC heater to an alumina substrate. To measure the thermal conductivity the heater heats the die for a few seconds after which the die allowed to cool down to the temperature of the substrate. The temperature of the cooling die is monitored and the time constant of the temperature decay is used to calculate the thermal conductivity of the die attach. Previous work demonstrated that this method can provide realistic information on the state of the die attach by relating the measured thermal conductivity to the shear strength of the die. Additionally the method is non destructive and can be used to monitor the degradation of the attach, such as fatigue cracking during thermal cycling. Here the test vehicle is modeled using the finite element method to get a better understanding of what temperatures the die attach is subjected to and to improve the thermal conductivity measurement.

scholarly journals Test Vehicle for Studying Thermal Conductivity of Die Attach Adhesives for High Temperature Electronics

2012 ◽  
Vol 188 ◽  
pp. 238-243
Author(s):  
Conor Slater ◽  
Fabrizio Vecchio ◽  
Thomas Maeder ◽  
Peter Ryser
Keyword(s):  
Thermal Conductivity ◽  
Shear Strength ◽  
High Temperature ◽  
Thick Film ◽  
Test Vehicle ◽  
High Temperature Electronics ◽  
Temperature Decay ◽  
Die Attach ◽  
Viable Method ◽  
Degree Of Degradation

Polymer adhesives offer a viable method for mounting silicon dies for high temperature applications. Here a test vehicle for comparing the thermal conductivity of different die attach materials is presented. The setup can be used to determine the degree of degradation of polymers. It consists of a mock die that has an integrated thick film heater, which is mounted onto a substrate. In operation, the substrate is placed on a heatsink and the die is heated. When the temperature reaches equilibrium the heater is switched off and the temperature of the die is measured as it cools. The time constant of the temperature decay is calculated to give the thermal conductivity. In this paper the thermal conductivity of an epoxy die attach adhesive is compared to its shear strength.

Improvement of Dielectric Performance of a Prototype AlN High Temperature Chip-level Package

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000052-000057 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
High Temperatures ◽  
Substrate Surface ◽  
Substrate Material ◽  
Glass Coating ◽  
Temperature Dependent ◽  
High Temperature Electronics ◽  
Dielectric Performance ◽  
Parasitic Parameters

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.

scholarly journals Measurement of the Thermal Conductivity and Rainwater Resistance of the Stabilized Mound Soil with Cement

2019 ◽  
Vol 9 (2) ◽  
pp. 3174-3179
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Resistance ◽  
Building Materials ◽  
Energy Savings ◽  
Environmental Benefits ◽  
Energy Crisis ◽  
Termite Mound ◽  
Cement Concrete ◽  
Naturally Occurring

This study is the result of experimental work in the field thermal of buildings. The study focuses on mounds termite’s clays. In this study a thermal analysis by the measurement of the thermal conductivity and the thermal resistance is carried out. This approach to determining the characteristics of materials has led to a better understanding of the possible choice of local building materials available in Chad. The estimation of thermal parameters of building materials plays a key role in a large number of scientific and industrial fields. Our choice has been focused on the termite mound soil which is currently of interest as a result of availability, energy crisis and that of housing.Unlike cement concrete, thé soil has long been used as a building material with practically many environmental benefits and considerable energy savings. The results obtained showed that the materials we used have a appreciable thermal properties. Brick from naturally occurring mound termite soil has better thermal resistance than brick made from mound termite soil, which means it is worked in advance. The influence of density on thermal resistance has been demonstrated. The stabilization of the cement reinforced the structure of the material and its resistance to erosion of the rain water

Performance Analysis of Heat Sinks Designed for Additive Manufacturing

2020 ◽  
Author(s):  
Andrew Scott White ◽  
David Saltzman ◽  
Stephen Lynch
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Additive Manufacturing ◽  
Technical Committee ◽  
Heat Sinks ◽  
Higher Power ◽  
Design Competition ◽  
Specific Material ◽  
Heat Sink Design ◽  
Better Than

Abstract Significant levels of heat are generated in contemporary electronics, and next generation devices will continue to demand higher power despite decreasing size; therefore, highly effective cooling schemes are needed. Simultaneously, advances in metal additive manufacturing have enabled production of complex heat transfer devices previously impossible to traditionally manufacture. This paper introduces three novel prototypes, originally designed for a prior ASME Student Heat Sink Design Competition sponsored by the K-16 (Heat Transfer in Electronic Devices) technical committee, to demonstrate the abilities of selective laser melting processes in the fabrication of A357 aluminum, EOS aluminum, and copper heat sinks. The performance of each of these prototypes has been determined experimentally, and the effects of specific material and design choices are analyzed. Comparisons of experimental results show that the copper and EOS aluminum prototypes performed better than the A357 aluminum due to increased thermal conductivity; however, the gains in thermal performance from EOS aluminum to copper were much lower despite the large difference in thermal conductivity.

Lead-Free Alternatives for Interconnects in High-Temperature Electronics

2017 ◽  
Author(s):  
Sandeep Mallampati ◽  
Liang Yin ◽  
David Shaddock ◽  
Harry Schoeller ◽  
Junghyun Cho
Keyword(s):  
Thermal Conductivity ◽  
Plastic Deformation ◽  
Shear Strength ◽  
High Temperature ◽  
Heat Dissipation ◽  
Volume Fraction ◽  
High Volume ◽  
Die Attach ◽  
Average Shear Strength ◽  
Average Shear

Predominant high melting point solders for high temperature and harsh environment electronics (operating temperatures from 200 to 250°C) are Pb-based systems, which are being subjected to RoHS regulations because of their toxic nature. In this study, high bismuth (Bi) alloy compositions with Bi-XSb-10Cu (X from 10 wt.% to 20 wt.%) were designed and developed to evaluate their potential as high-temperature, Pb-free replacements. Reflow processes were developed to make die-attach samples made out of the cast Bi alloys. In particular, die-attach joints made out of Bi-15Sb-10Cu alloy exhibited an average shear strength of 24 MPa, which is comparable to that of commercially available high Pb solders. These alloy compositions also retained original shear strength even after thermal shock between −55°C and +200°C and high temperature storage at 200°C. Brittle interfacial fracture sometimes occurred along the interfacial NiSb layer formed between Bi(Sb) matrix and Ni metallized surface. In addition, heat dissipation capabilities, using flash diffusivity, were measured on the die-attach assembly, compared to the corresponding bulk alloys. The thermal conductivity of all the Bi-Sb alloys was higher than that of pure Bi. By creating high volume fraction of precipitates in a die-attach joint microstructure, it was feasible to further increase thermal conductivity of this joint to 24 W/m·K, which is three times higher than that of pure Bi (8 W/m·K). Bi-15Sb-10Cu alloy has so far shown the most promising performance as a die-attach material for high temperature applications (operated over 200°C). Hence, this alloy was further studied to evaluate its potential for plastic deformation. Bi-15Sb-10Cu alloy has shown limited plastic deformation in room temperature tensile testing, in which premature fracture occurred via the cracks propagated on the (111) cleavage planes of rhombohedral crystal structure of the Bi(Sb) matrix. The same alloy has, however, shown up to 7% plastic strain under tension when tested at 175°C. The cleavage planes, which became oriented at smaller angles to the tensile stress, contributed to improved plasticity in the high temperature test.

scholarly journals Energy and Exergy Viability Analysis of Nanofluids As A Coolant for Microchannel Heat Sink

2019 ◽  
Vol 16 (1) ◽  
pp. 6090-6107
Author(s):  
S. Mukherjee ◽  
Purna Chandra Mishra ◽  
P. Chaudhuri
Keyword(s):  
Thermal Resistance ◽  
Weight Fraction ◽  
Constant Heat Flux ◽  
Heat Sinks ◽  
Exergy Loss ◽  
Simultaneous Increase ◽  
Substrate Thickness ◽  
Pumping Power ◽  
Rectangular Microchannel ◽  
Viability Analysis

The present paper aims to provide a theoretical analysis of energy, exergy loss and pumping power demand of water-based Al2O3, TiO2, CuO, SiC nanofluids flow through rectangular microchannel heat sinks under constant heat flux condition. The weight fraction of nanoparticles was varied from 0% to5%. Thermal resistance decreased with particle inclusion in the base fluid. Decease in thermal resistance and increase in microchannel efficiency was observed with the application of nanofluids. However, reduction in thermal resistance and rise in efficiency is more with Al2O3 –water and CuO-water nanofluids rather than TiO2-water and SiC-water nanofluids. Addition of nanoparticles in base fluids was found suitable for reducing thermal resistance and increasing efficiency of microchannel but at the same time, an increase in pumping power with the rise in weight fraction was also observed. The maximum reduction in thermal resistance with a simultaneous increase in thermal efficiency was observed using CuO-water nanofluids at 5% wt. fraction. The estimated exergy loss is relatively higher in CuO-water and Al2O3-water nanofluids than TiO2-water and SiC-water nanofluids. The rise in ambient temperature effectively reduces the exergy loss. Maximum exergy loss was obtained with CuO nanofluids at 5% wt. fraction while the minimum was observed with water. The effect of substrate thickness on efficiency and exergy loss was also estimated.

End of Life Failure Modes for Packaged SOI Devices for Signal Conditioning and Processing Applications

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000327-000334
Author(s):  
S T Riches ◽  
C Johnston ◽  
A Crossley ◽  
P Grant
Keyword(s):  
High Temperature ◽  
End Of Life ◽  
Failure Modes ◽  
Reliability Data ◽  
High Temperature Electronics ◽  
Die Attach ◽  
Aero Engine ◽  
Endurance Tests ◽  
Soi Devices

Silicon on Insulator (SOI) device technology has been shown to be capable of functioning satisfactorily at operating temperatures of >200°C. Most of the applications to date have required performance for short times (<2,000 hours) at the highest operating temperatures of up to 225°C in down-well drilling applications. There is interest in extending the endurance of high temperature electronics into aero-engine and other applications where a minimum 20 year operating life is stipulated. In order to gain confidence in high temperature electronics that can meet this requirement, accurate reliability data are needed and end of life failure modes need to be identified. Most of the reliability data on the high temperature endurance of the integrated circuit is generated with little consideration of the packaging technologies, whilst most of the reliability data pertinent to high temperature packaging technologies uses test pieces rather than devices, which limits any conclusions relating to long term electrical performance. This paper presents results of temperature storage and cycling endurance studies on SOI devices combined with high temperature packaging technologies relevant to signal conditioning and processing functions for sensors in down-well and aero-engine applications. The endurance studies have been carried out for up to 11,088 hours at 250°C, with functioning devices being tested periodically at room temperature, 125°C and 250°C and rapid thermal cycling from −40°C to +225°C. Different die attach and wire bond options have been included in the study and the performance of several functional blocks on the SOI device has been tracked over the endurance tests. The failure modes observed on completion of the endurance tests include die cracking and deterioration of the device bond pads accelerated due to degradation of some die attach materials. The routes to achieving stable long term performance of packaged devices at temperatures of 250°C will be outlined.

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