Interfacial Microstructure Evolution of Low Melting Point Alloy Joints After Thermal Treatments

In the application of high-performance computing (HPC), a considerable heat generated from chip require a high-efficient thermal management and a thermal interface material (TIM) with a high thermal conductivity to be transferred sufficiently to heat sink (HS). Metal TIMs are promising materials wit...

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Bibliographic Details
Main Authors: Chen, Cheng-Lun, Hung, Liang-Yih, Lee, Yueh Yang, Shih, Chih-Yuan, Wang, Yu-Po
Format: Conference Proceeding
Language:English
Subjects:
Conductivity
Metals
Nickel
Silver
Surface finishing
Surface resistance
Thermal management
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Summary:In the application of high-performance computing (HPC), a considerable heat generated from chip require a high-efficient thermal management and a thermal interface material (TIM) with a high thermal conductivity to be transferred sufficiently to heat sink (HS). Metal TIMs are promising materials with high thermal conductivity, which can be mainly classified into two types: solder-TIMs and nano-Ag sinter paste. Solder-TIMs can be melted and filled in the gap between the surfaces of chip and HS to form a metal joint and form a heat conduction path, such as indium, indium-base alloys, tin and tin-base alloys. The nano-Ag sintering paste is composed of nano- or micro- silver particles and a polymer matrix. At a high temperature and under a high-pressure condition, nano-Ag particles can be sintered to form a silver network, or even be a silver bulk with microporous, which can achieve a high thermal conductivity. However, there is a high stress around the interface between chip and metal TIMs (nano-Ag sintering or certain solder TIM) after joint process, which may cause delamination or crack in package. In-base alloy and Ga-base alloy are low melting point alloys, and the melting point of the alloys can be designed to be lower than the surface temperature of chip as device operating, or even below room temperature. When low melting point alloys become or remain liquid state, it may be beneficial to reduce the stress within the package. However, the low melting point alloys may react with Ni and Cu of HS, which may affect the reliability of package. So, the interfacial microstructure evolution of low melting point alloys jointed with Ni/Cu-HS and Cu/Ni/Au surface finish have been investigated in this study.
ISSN:2150-5942
DOI:10.1109/IMPACT59481.2023.10348882