Tin Whiskers Mitigation Strategy through Composite Tin Plating with Ni-nanoparticles

本研究项目的主要目的是了解复合镀锡对锡晶须成核和生长的影响。考察这一目标的方法如下：1)开发一种工艺，以制备一种由锡作为基质和镍纳米颗粒作为增强剂的复合阳极，该复合阳极将均匀分布在锡基质中。2)寻找一种最佳的化学溶液，使锡和镍纳米颗粒在电镀过程中从阳极平行输送到阴极。3)开发一种加速锡晶须成核和生长的方法。4)研究了镍纳米颗粒对锡晶须成核和生长的影响机制，如内应力的类型、强度和来源，镍衬底的存在，以及扩散过程。利用X射线衍射、聚焦离子束、扫描俄歇显微镜和扫描电子显微镜等多种技术研究晶须生长动力学以及纳米镍颗粒的存在对晶须生长的影响。在锡中添加纳米镍颗粒将通过阻止晶须的萌生和生长来极大地改变焊点的形态，并改变焊料与衬底之间的界面。如果成功，这项研究将为电子元器件和组件的制造商/用户提供一种环保的镀锡技术，通过消除锡须形式的导电丝的生长，大大降低电子元器件和组件的可靠性风险问题。该项目将在与材料科学、电镀和电物理-机械性能测试相关的研究、培训和教育方面产生新的方向。

The main objective of this research project is to understand the effect of composite tin plating on the nucleation and growth of tin whiskers. The approach to examining this objective is the following: 1) Develop a process to fabricate a composite anode that consists of tin as a matrix and nickel nanoparticles as a reinforcement that would be uniformly distributed through the tin-matrix. 2) Find an optimal chemical solution that will provide a parallel transport of tin and nickel nanoparticles from the anode to the cathode in the electroplating process. 3) Develop a procedure for accelerated nucleation and growth of tin whiskers. 4) Study the effect of nickel nanoparticles on the mechanisms that affect the nucleation and growth of tin whiskers, such as type, intensity, and source of internal stresses, the presence of nickel underlay, and the diffusion process. Various techniques, including x-ray diffraction, focused ion beam, scanning auger microscopy, and scanning electron microscopy will be used to study the whisker growth kinetics and effect of the presence of nickel nanoparticles on its growth. The addition of Nickel nanoparticles to tin will change drastically the morphology of the solder joint by blocking the initiation and growth of whiskers as well as change the interface between solder and substrates. If successful, this research will provide manufacturers/users of electronic components and assemblies with an environmentally friendly tin-plating technology that will drastically decrease reliability risk issue of electronic components and assemblies by eliminating the growth of electrically conductive filaments in the form of tin whiskers. The project will generate new directions in research, training and education related to materials science, electroplating, and the testing of electro-physical-mechanical properties.