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1.
The specific thermal resistance values of several thermal interface materials (TIMs) intended to thermally enhance Cu contact pairs and their degradation under isothermal ageing at 170 °C have been investigated using Cu stack samples consisting of 10 Cu discs and 9 layers of the TIMs. The results obtained indicate that the specific thermal resistance values of the as-prepared Cu stack samples, one with conductive Ag thermal grease, one with Sn–3.5Ag solder joints and one with 25 μm thick Sn foil as TIMs are significantly lower than those of the Cu stack sample without any TIM. However, after the isothermal ageing at 170 °C for 90 days, the specific thermal resistance values of the samples with these TIMs are not substantially different from those of the sample without any TIM. Also reported in this paper is an estimation of testing errors for the specific thermal resistance values, microstructure characterization of the aged samples and effect of the degradation of these TIMs on the thermal performance of a high-temperature half bridge power switch module. 相似文献
2.
Kercher D.S. Jeong-Bong Lee Brand O. Allen M.G. Glezer A. 《Components and Packaging Technologies, IEEE Transactions on》2003,26(2):359-366
This research is an effort to demonstrate the applicability of miniaturized synthetic jet (microjet) technology to the area of thermal management of microelectronic devices. Synthetic jets are jets which are formed from entrainment and expulsion of the fluid in which they are embedded. Design issues of microjet cooling devices are discussed along with characterization of excitation elements and the turbulent synthetic jets produced thereby. Geometrical parameters of the microjet cooling devices were empirically optimized with regards to cooling performance. The cooling performance of the optimized microjets was compared with previous theoretical and empirical studies of conventional jet impingement. The cooling performance of the microjet devices has been investigated in an open environment as well as in a vented and closed case environment. In such experiments, the synthetic jet impinges normal to the surface of a packaged thermal test die, comprising a heater and a diode-based temperature sensor. This test assembly allows simultaneous heat generation and temperature sensing of the package, thereby enabling assessment of the performance of the synthetic jet. Using microjet cooling devices, a thermal resistance of 30.1/spl deg/C/W has been achieved (when unforced cooling is used, thermal resistance is 59.6/spl deg/C/W) when the test chip is located at 15mm spacing from the jet exit plane. In order to more directly compare and scale the cooling results, a preliminary study on heat transfer correlations of the microjet cooling device has been performed. Finally, a comparison of the performance of the microjet cooler with standard cooling fans is given. 相似文献
3.
Zhijun Zuo Hoover L.R. Phillips A.L. 《Components and Packaging Technologies, IEEE Transactions on》2002,25(4):629-634
This paper presents a thermal architecture concept for analysis of thermal problems and solutions existing in electronics systems. The thermal problems are categorized into a total of seven levels from chip to system. Advanced thermal technologies for addressing the thermal problems at all seven levels are discussed. Integrating the thermal architecture with the electronic architecture can significantly improve the effectiveness of the thermal management. 相似文献
4.
Power electronics cooling effectiveness versus thermal inertia 总被引:1,自引:0,他引:1
Today, the popularity of power electronics integration is increasing. Despite the prospect of fully integrated module, including features like driving and control electronics, protection, power integration has not taken-off for medium to high power electronics applications. Manufacturing issues such as yield, reliability and return-on-investment for a new fabrication line are the major blocking points. As a first step toward integrated modules, integration of the cooling system appears realistic and cost effective. Increasing the cooling effectiveness could double the output current of an inverter while using the same amount of silicon. On the other hand, integrated cooling leads to small thermal inertia, which can generate high temperature variation under load cycling condition. This paper highlights the relationship between cooling effectiveness and thermal inertia. Typical performances of several cooling systems are compared under load cycling condition to explain how to take into account the variation of the losses in the choice of a cooling technique at the design stage. As an example, a standard liquid cooled plate performed similar to an integrated microchannel network for specific load variation frequencies. 相似文献
5.
This paper presents new investigations on the aging of Thermal Interface Materials (TIMs) subjected to thermal cycling conditions. The challenge was to design a specific and original set-up in order to not only undergo avionic temperature mission profile (?50 °C/+150 °C) but also to perform standardized thermal characterization at always same conditions. Thermal conductivity is used as aging indicator. Several TIM materials (change phase, graphite and polymer based) have undergone more than 1500 of such cycles. As a result, only the phase change material thermal interface has been affected with a 30% increase of initial thermal resistance. 相似文献
6.
Polyol-based phase-change thermal interface materials 总被引:1,自引:0,他引:1
Polyol-based phase-change thermal interface materials that exhibit high thermal contact conductance and thermal stability
have been developed for microelectronic cooling. By using a diol (polycaprolactone or polyester diol in the form of 2-oxepanone)
of molecular weight 1,000–2,000 amu, along with 4 vol.%-hexagonal boron nitride particles, this work attained thermal contact
conductance (at 70°C, across copper surfaces) that is higher than that attained by using paraffin wax, polyether glycol, polyethylene
glycol, or tetradecanol (in place of the diol) and that attained by commercial phase-change thermal interface materials. The
thermal stability of the diol is superior to the other phase change materials mentioned above, although the heat of fusion
is lower. Boron nitride is more effective than carbon black (also 4 vol.%) for enhancing the conductance, but carbon black
diminishes the heat of fusion less than does boron nitride. 相似文献
7.
Hiroyuki Sakaki 《Journal of Electronic Materials》1990,19(10):1151-1151
8.
J.P Gwinn R.L Webb 《Microelectronics Journal》2003,34(3):215-222
The increasing power and reduced die size of CPUs used in computers increases a need for significantly improved thermal interface materials (TIM). The TIM is used to reduce contact resistance at the CPU-heat sink interface. This work provides a state-of-the-art assessment on ‘thermal interface materials’, including fundamentals, materials used, their performance, and how interface resistance is measured. The performance of new commercial interface materials is given, as well as discussion of the advantages and disadvantages of different materials. The report notes that the recommended interface test method does not necessarily duplicate the installation and operating conditions in an actual computer installation. Recommendations are presented on the design and operation of an apparatus intended to simulate actual computer installation conditions. The innovative Penn State ‘low melting point alloy’ thermal interface material is described and compared to other commercial materials. 相似文献
9.
In this paper the aspects of thermal interface material characterization are discussed from a practical point of view. A novel method based on existing measurement standards is introduced for a quick and repeatable thermal conductivity measurement of nanoparticle-based thermal greases. The effect of the surface roughness of the DUT fixture is evaluated, and a method is introduced for the long-term reliability testing of these nanocomposites. 相似文献
10.
The characteristics of idealized photochromic materials are defined. The optical properties of rare-earth-doped CaF2 and transition-metal-doped SrTiO3 photochromic materials are outlined. The operational parameters of these inorganic photochromic materials pertinent to electrooptic applications are described. 相似文献
11.
《Microelectronics Reliability》2002,42(9-11):1597-1604
12.
Krishnan S. Garimella S.V. Kang S.S. 《Components and Packaging Technologies, IEEE Transactions on》2005,28(2):281-289
A hybrid heat sink concept which combines passive and active cooling approaches is proposed. The hybrid heat sink is essentially a plate fin heat sink with the tip immersed in a phase change material (PCM). The exposed area of the fins dissipates heat during periods when high convective cooling is available. When the air cooling is reduced, the heat is absorbed by the PCM. The governing conservation equations are solved using a finite-volume method on orthogonal, rectangular grids. An enthalpy method is used for modeling the melting/re-solidification phenomena. Results from the analysis elucidate the thermal performance of these hybrid heat sinks. The improved performance of the hybrid heat sink compared to a finned heat sink (without a PCM) under identical conditions, is quantified. In order to reduce the computational time and aid in preliminary design, a one-dimensional fin equation is formulated which accounts for the simultaneous convective heat transfer from the finned surface and melting of the PCM at the tip. The influence of the location, amount, and type of PCM, as well as the fin thickness on the thermal performance of the hybrid heat sink is investigated. Simple guidelines are developed for preliminary design of these heat sinks. 相似文献
13.
Direct bonded copper (DBC) are produced by high temperature ( >1000 ° C) bonding between copper and a ceramic (usually alumina). They are commonly used in power electronics. However, their reliability when exposed to thermal cycling is still an issue, that could be addressed by advanced numerical simulations. This paper describes the identification of the parameters for a numerical model that uses finite elements with cohesive zones. This identification is based on careful mechanical characterization of all components of the DBC (ceramic, copper and interface) using an innovative approach based on image correlation. 相似文献
14.
RFICs were thinned down and transferred to the flexible substrate by the proposed polydimethylsiloxane-substrate transfer technology (PSTT). Measurement results show the feasibility of the proposed technique, and furthermore prove its ability to reduce the substrate loss in the high frequency range. With PSTT, the quality factor of a 3.5 turns inductor is improved from 9.3 to 13.4 and the noise figure of a 5-6 GHz direct-conversion receiver is reduced by 0.5 dB. The demonstration reveals the potential of PSTT for the flexible electronics in RFICs applications. 相似文献
15.
Maydanik Y.F. Vershinin S.V. Korukov M.A. Ochterbeck J.M. 《Components and Packaging Technologies, IEEE Transactions on》2005,28(2):290-296
Loop heat pipes (LHPs) are highly efficient heat-transfer devices, which have considerable advantages over conventional heat pipes. Currently, miniature LHPs (MLHPs) with masses ranging from 10-20 g and ammonia and water as working fluids have been developed and tested. The MLHPs are capable of transferring heat loads of 100-200 W for distances up to 300 mm in the temperature range 50-100/spl deg/C at any orientation in 1-g conditions. The thermal resistance for these conditions are in the range from 0.1 to 0.2 K/W. The devices possess mechanical flexibility and are adaptable to different conditions of location and operation. Such characteristics of MLHPs open numerous prospects for use in cooling systems of electronics and computer systems. 相似文献
16.
17.
Ever since RoHS was implemented in 2006, Sn3.0Ag0.5Cu (SAC305) has been the primary lead-free solder for attaching electronic devices to printed circuit boards (PCBs). However, due to the 3.0 wt% Silver (Ag) in SAC305, companies have been looking at less expensive solder alternatives, especially for use in inexpensive products that have short operating lives and are used in mild application conditions. This paper reviews new lead-free solder alternatives and the trends in the industry, including SnCu-based solders, SnAgCu solders with Ag content < 1.0 wt%, SnAg solders, and no-Ag low-temperature solders (e.g., SnBi-based solders). The analysis is conducted for reflow, wave, and rework conditions and for packaged and flip-chip devices. 相似文献
18.
Zuo Z.J. North M.T. Wert K.L. 《Components and Packaging Technologies, IEEE Transactions on》2001,24(2):220-225
This paper discusses an advanced heat pipe mechanism that has the potential of achieving heat flux capabilities over 250 W/cm2. The mechanism utilizes thermally driven pulsating two-phase flow to achieve high heat flux capability and heat transfer coefficient. A simplified hydrodynamic model in was developed to guide the proof-of-concept heat pipe design. A more detailed numerical model was also developed and will be solved to predict the heat pipe's thermal performance. Test results of proof-of-concept heat pipes verified the heat flux capability of the advanced mechanism and the accuracy of the simplified model. Pulsating heat pipes are feasible approaches to removing increasing heat dissipation densities in electronic equipment 相似文献
19.
Xian Huang 《半导体学报》2018,39(1):37-46
Bioresorbable electronics is a new type of electronics technology that can potentially lead to biodegradable and dissolvable electronic devices to replace current built-to-last circuits predominantly used in implantable devices and consumer electronics.Such devices dissolve in an aqueous environment in time periods from seconds to months,and generate biological safe products.This paper reviews materials,fabrication techniques,and applications of bioresorbable electronics,and aims to inspire more revolutionary bioresorbable systems that can generate broader social and economic impact.Existing challenges and potential solutions in developing bioresorbable electronics have also been presented to arouse more joint research efforts in this field to build systematic technology framework. 相似文献