Purpose

The purpose of this paper is to investigate the effect of titanium nitride (TiN) on microstructure and composition of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints under a large temperature gradient.

Design/methodology/approach

In this paper, SAC305 lead-free composite solder containing 0.05 Wt.% TiN was prepared by powder metallurgy method. A temperature gradient generator was designed and the corresponding samples were also prepared. The microstructural evolution, internal structure and elemental content of SAC305 and SAC305/TiN solder joints before and after thermal loading were comparatively studied.

Findings

The experimental results show that the addition of the TiN reinforcing phase can effectively inhibit the diffusion and migration of copper atoms and, therefore, affect the distribution of newly formed Cu-Sn IMC in solder joints under the condition of thermal migration (TM). Compared with the SAC305 solder joint, the interconnection interface and internal structure of the composite solder joint after 600 h of TM are also relatively complete.

Originality/value

The TiN reinforcing phase is proven effective to mitigate the TM behavior in solder joints under thermal stressing. Specifically, based on the observation and analysis results of microstructure and internal structure of composite solder joint, the TiN particle can change the temperature gradient distribution of the solder joint, so as to suppress the diffusion and migration of Sn and Cu atoms. In addition, the results of Micro-CT and compositional analysis also indicate that the addition of TiN reinforcement is very helpful to maintain the structural integrity and the compositional stability of the solder joint. Different from other ceramic reinforcements, TiN has good thermo- and electro-conductivity and the thermal-electrical performance of composite solder will not be significantly affected by this reinforcement, which is also the main advantage of selecting TiN as the reinforcing phase to prepare composite solder. This study can not only provide preliminary experimental support for the preparation of high reliability lead-free composite solder but also provide a theoretical basis for the subsequent study (such as electro-thermo distribution in solder joints), which has important application significance.

中文翻译：

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SAC305/TiN复合焊料在热应力作用下的微观结构和成分演变

目的

本文的目的是研究氮化钛 (TiN) 在大温度梯度下对 96.5Sn3Ag0.5Cu (SAC305) 无铅焊点的微观结构和成分的影响。

设计/方法/方法

本文采用粉末冶金法制备了含0.05 Wt.% TiN的SAC305无铅复合焊料。设计了温度梯度发生器并制备了相应的样品。对比研究了热加载前后SAC305和SAC305/TiN焊点的显微组织演变、内部结构和元素含量。

发现

实验结果表明，TiN增强相的加入能有效抑制铜原子的扩散和迁移，从而影响热迁移（TM）条件下新形成的Cu-Sn IMC在焊点中的分布。与SAC305焊点相比，TM 600 h后复合焊点的互连接口和内部结构也比较完整。

原创性/价值

事实证明，TiN 增强相可有效减轻热应力下焊点的 TM 行为。具体而言，基于对复合焊点微观结构和内部结构的观察和分析结果，TiN颗粒可以改变焊点的温度梯度分布，从而抑制Sn和Cu原子的扩散和迁移。此外，Micro-CT和成分分析结果也表明，添加TiN增强材料对保持焊点的结构完整性和成分稳定性非常有帮助。与其他陶瓷增强材料不同，TiN 具有良好的导热和导电性，复合焊料的热电性能不会受到这种增强材料的显着影响，这也是选择TiN作为补强相制备复合焊料的主要优点。本研究不仅可为高可靠性无铅复合焊料的制备提供初步的实验支持，而且为后续研究（如焊点中的电热分布）提供理论依据，具有重要的应用意义。