Soldering & Surface Mount Technology ( IF 2 ) Pub Date : 2019-12-05 , DOI: 10.1108/ssmt-07-2019-0023 Yansong Tan , Xin Li , Xu Chen , Zhenwen Yang , Guo-Quan Lu
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.
中文翻译:
低压辅助烧结银结合大面积DBA板的可行性研究与表征
目的
本文旨在利用纳米银浆设计一种用于超大面积直接粘结铝(DBA)板的新粘结方法。它比较了几种常用的键合方法,并证明了针对大面积键合优化低压辅助双层印刷银烧结技术的可行性,以提高结温高,功率密度高和功率电子模块的热导率。更高的可靠性。
设计/方法/方法
通过使用透明玻璃作为基材来优化粘合轮廓。因此,结合质量可以通过光学观察直接表征。烧结后,结合的DBA样品通过无损X射线计算机断层扫描系统,配有能量色散谱仪的扫描电子显微镜进行表征。最后,通过剪切试验表征了粘结应力的演变。
发现
成功开发出由六步法组成的低压辅助大面积双层印刷粘合工艺,以粘合尺寸为50.8×25.4 mm的DBA基板。烧结银键合线的厚度在33至74 µm之间,平均孔隙率为12.5%。剪切强度沿DBA / DBA粘结样品的长度分布为9.7至18.8 MPa,平均剪切强度为15.5 MPa。典型的裂缝主要在烧结银层中传播,部分沿镍层传播。
研究局限/意义
结合应力需要进一步改善。同时,鼓励对热和电性能进行进一步测试。
实际影响
如果纳米银浆可用作超大面积粘结的热界面材料,则热性能将得到改善。
社会影响
该论文加快了纳米银浆在超大面积DBA粘结中的使用。
创意/价值
所提出的粘合方法大大降低了粘合压力。