Ag-Diamond Heatspreader for Power Devices
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2024-04-12 |
| Journal | IMAPSource Proceedings |
| Authors | Tomonao Okubo |
Abstract
Section titled āAbstractāAs electric devices are developed for high-powered, high-speed and high capacity at a rapid pace, their thermal design are considered more important. With thermal conductivity (TC) of about 400 W / mK coupled with low-cost, Cu is widely used as a packaging material for electronic devices. However, its coefficient of thermal expansion (CTE) is 17 ppm / K, which is much different from that of Si, GaAs, and SiC devices, pose a risk of lowered reliability of packaged devices, such as cracks at solder joints or damage to semiconductor devices. Therefore, a packaging material for a high-performance device requires not only high TC but also a CTE close to that of the semiconductor chip and the packaging materials. To achieve this goal, we have developed a Ag-Diamond composite material. This new material has TC of 600 W / mK or more, and CTE 9.0 ppm / K (R.T. to 400 deg.C). It can also stand 1000 heat-cycles at -65 to 150 C, and maintain TC over 600 W / mK with minimal TC degradation of 4%. Also, the material is found to maintain TC over 600 W / mK after two cycles of thermal stresses at 800 deg.C, a temperature for brazing process for ceramic packages. Lastly, our simulation using Ag-Diamond composite as a heatspreader for a GaN (RF power) device has demonstrated that the material yields less thermal stress, >=-8 Mpa, compared with a GaN device directly bonded on copper base plate, and also lower Tj on GaN device, > -26 C, vs. GaN device directly bonded on Cu-Mo composite.