Experimental Investigation on the Heat Dissipation Performance of Bismuth-Based Alloy Thermal Conductive Sheet

At present, the existing thermal interface materials (TIMs) cannot meet the heat dissipation requirements of some high-power density electronic devices. In this study, Bi-based low melting point alloy was made into a thermal conductive sheet to reduce the interface thermal resistance. The thermal conductivity of a thermal conductive sheet was found to be 37.83 W/(m·K), 10 times higher than Dow Corning 5021 thermal grease. In addition, the surface morphology of the Bi-based alloy thermal conductive sheet was changed in this experiment, which was divided into textured and planer type, and the measured interface thermal resistance values lower than Dow Corning 5021 thermal grease by approximately 30% and 27%, respectively. The results prove this Bi-based alloy thermal conductive sheets have the ideal heat dissipation performance and their wide application prospects in high-power density electronic devices.

A Study on the Thermal Conductivity of Thermal Grease According to Cu-Ni Content

An increase in power consumption density is related to the internal thermal characteristics of an electronic device, and the heat dissipation of the device is directly related to the high performance and miniaturization of the device. TIM (thermal interface material) with excellent internal heat dissipation performance are mainly used to improve the heat dissipation performance of electronic devices. Recently, the need for a high-efficiency TIM with high-performance thermal conductivity and low thermal contact resistance has increased. In this study, thermal grease was prepared by mixing Cu-Ni nanopowders with silicon oil, the thermal grease was then used as a heat transfer material. Compared to silicone thermal grease, the thermal conductivity of all prepared samples was excellent. In particularly, thermal conductivity was improved by about maximum 212% compared to that of thermal silicone of thermal grease mixed with Cu-Ni powder.

Development of High Thermally Conductive Die Attach for TIM Applications

High-power semiconductor applications require a thermal interface die attach material with high thermal conductivity to efficiently release the heat generated from these devices. Current thermal interface material solutions such as thermal grease, thermal pads, and silicones have been industry standards, however may fall short in performance for high-temperature or high-power applications. This article focuses on development of a cutting-edge die attach solution for thermal interface management, focusing on fusion-type epoxy-based Ag adhesive with an extremely low storage modulus and the thermal conductivity reaching up to 30 W/mK, and also very low-modulus, low-temperature pressureless sintering silver die attach with a thermal conductivity of 70 W/mK.

Thermal Conductivity Characterization of Thermal Grease Containing Copper Nanopowder

As electronic devices and mainboards become smaller, the need for thermal conductive materials having excellent internal heat dissipation is increasing. In this study, nano thermal grease was prepared by mixing in copper nanopowder, which is used as a heat transfer medium in thermal grease, which is a kind of thermal conductive material, with silicon oil. In addition, copper powder was mixed with graphene and alumina, respectively, and the thermal conductivity performance was compared. As a result, the thermal conductivity improved by 4.5 W/m·k over the silicon base, and the upward trend of thermal conductivity increased steadily up to 15 vol. %, and the increasing trend decreased after 20 vol. %. In addition, the increased rate of thermal conductivity from 0 to 5 vol. % and 10 to 15 vol. % was the largest.

A Modification of Offset Strip Fin Heatsink with High-Performance Cooling for IGBT Modules

For reliability and thermal management of power devices, the most frequently used technique is to employ heatsinks. In this work, a new configuration of offset strip fin heatsink based on using the concept of curvy fins and U-turn is proposed with the aim of improving the heat transfer performance. With this aim, a three-dimensional model of heatsink with Silicon Insulated-Gate Bipolar Transistors (IGBTs) and diodes, solder, Direct Bonded Copper (DBC) substrate, baseplate and thermal grease is developed. Richardson’s extrapolation is used for increasing the accuracy of the numerical simulations and to validate the simulations. To study the effectiveness of the new offset design, results are compared with conventional offset strip fin heatsink. Results show that in aspects of design of heatsinks (including heat transfer coefficient, maximum chip temperature and thermal resistance), the new introduced model has advantages compared to the conventional offset strip fin design. These enhancements are caused by the combination of the longer coolant passage in the heatsink associated with generation of disturbance and recirculation areas along the curvy fins, creation of centrifugal forces in the U-turn, and periodic breaking up boundary layers. Also, it is shown that due to narrower passage and back-and-forth route, the new introduced design can handle the hot spots better than conventional design.

Development of High Thermally Conductive Die Attach for TIM Applications

High power semiconductor applications require a Thermal Interface Die Attach Material with high thermal conductivity to efficiently release the heat generated from these devices. Current Thermal Interface Material solutions such as thermal grease, thermal pads and silicones have been industry standards, however may fall short in performance for high temperature or high-power applications. This presentation will focus on development of a cutting-edge Die Attach Solution for Thermal Interface Management, focusing on Fusion Type epoxy-based Ag adhesive with an extremally low Storage Modulus and the Thermal Conductivity reaching up to 30W/mK, and also Very Low Modulus, Low-Temperature Pressureless Sintered Silver Die Attach with the Thermal Conductivity of 70W/mK.