材料科学
烧结
复合材料
扫描电子显微镜
多孔性
焊接
抗剪强度(土壤)
扫描声学显微镜
粘结强度
图层(电子)
声学显微镜
光学
显微镜
胶粘剂
土壤科学
土壤水分
物理
环境科学
作者
Yansong Tan,Xin Li,Xu Chen,Zhenwen Yang,Gongxuan Lü
出处
期刊:Soldering & Surface Mount Technology
[Emerald (MCB UP)]
日期:2019-12-05
卷期号:32 (3): 129-136
被引量:6
标识
DOI:10.1108/ssmt-07-2019-0023
摘要
Purpose This paper aims to use nano-silver paste to design a new bonding method for super-large-area direct-bonded-aluminum (DBA) plates. It compared several frequently used bonding methods and proved the feasibility of an optimized low-pressure-assisted double-layer-printed silver sintering technology for large-area bonding to increase the thermal conductivity of power electronic modules with high junction temperature, higher power density and higher reliability. Design/methodology/approach The bonding profile was optimized by using transparent glasses as substrates. Thus, the bonding qualities could be directly characterized by optical observation. After sintering, the bonded DBA samples were characterized by nondestructive X-ray computed tomography system, scanning electron microscopy equipped with an energy dispersive spectrometer. Finally, bonding stress evolution was characterized by shear tests. Findings Low-pressure-assisted large-area double-layer-printed bonding process consisting of six-step was successfully developed to bond DBA substrates with the size of 50.8 × 25.4 mm. The thickness of the sintered-silver bond-line was between 33 and 74 µm with the average porosity of 12.5 per cent. The distribution of shear strength along the length of DBA/DBA bonded sample was from 9.7 to 18.8 MPa, with average shear strength of 15.5 MPa. The typical fracture primarily propagated in the sintered-silver layer and partially along the Ni layer. Research limitations/implications The bonding stress needs to be further improved. Meanwhile, the thermal and electrical properties are encouraged to test further. Practical implications If nano-silver paste can be used as thermal interfacial material for super-large-area bonding, the thermal performance will be improved. Social implications The paper accelerated the use of nano-silver paste for super-large-area DBA bonding. Originality/value The proposed bonding method greatly decreased the bonding pressure.
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