超声辅助Sn基钎料快速反应形成全化合物接头原理的研究

发布时间：2018-04-17 12:53

  本文选题：功率电子 + 芯片键合　； 参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：随着电子科学技术的发展与普及,微电子器件朝着小型化、轻便化、良好的机电性能以及低成本的方向发展,且愈发恶化的器件工作环境,像高温、大电流和潮湿的气氛,使得芯片封装面临诸多挑战。与此同时,第三代宽禁带半导体Si C和Ga N的出现,在高温功率电子领域将取代目前Si芯片。因此,加强新的封装材料和方法的研究,对于Si C芯片在汽车电子、航空航天、军事、发光二极管等高温功率电子中优良性能的发挥起着至关重要的作用。本文基于瞬态液相法的原理,将钎料膏中Sn合金颗粒优化为Sn/Ni混合颗粒,并施加超声作用,既实现了接头的快速成型,同时生成的化合物接头具有良好的高温稳定性。通过试验,系统地研究了钎料中Ni的含量、Ni颗粒尺寸以及超声功率对接头组织和性能的影响。研究发现,Ni颗粒的尺寸直接影响到钎料的润湿性和接头的组织形貌,而且接头内生成的Ni3Sn4的含量随着钎料中Ni的增加而增加。当焊接温度为250℃、超声功率为500W、焊接时间为10s时,采用Sn-24%Ni钎料作为中间层能够获得剪切强度为43.4MPa,电阻率为24.09μΩ·cm的高性能全化合物接头。经过300℃空气中高温老化72h后,接头组织无相变发生,剪切强度有所下降,但仍高达33.4MPa。当增加钎料中Ni的颗粒尺寸为20μm、含量为40%时,在250℃回流90min后,获得了Ni与Ni3Sn4组成的低杨氏模量的混合组织接头。深入探讨了界面化合物生长规律和超声作用机制,确定Ni-Sn体系中首先生成的化合物为Ni3Sn4,在不施加超声情况下,Ni3Sn4的生长主要依靠Ni原子的扩散,生长规律呈类抛物线形式。通过计算得知,Ni3Sn4在250℃时的生长常数较小,仅为4.643×10-11cm2/s。超声的加入能够很好的解决单独依靠原子扩散而造成化合物生长速率较低的问题,它的“空化”和“声流”作用能够将Ni周围形成的Ni3Sn4层破碎,增大Ni与Sn的直接接触面积,极大加快冶金反应的进行速率,从而实现化合物接头的快速成型。
[Abstract]:With the development and popularization of electronic science and technology, microelectronic devices are developing towards miniaturization, portability, good electromechanical performance and low cost, and worsening working environment, such as high temperature, high current and humid atmosphere,Chip packaging faces many challenges.At the same time, the appearance of the third generation wide band gap semiconductors, sic and gan, will replace the current Si chips in the field of high-temperature power electronics.Therefore, strengthening the research of new packaging materials and methods plays an important role in the performance of sic chips in automotive electronics, aerospace, military, light-emitting diodes and other high-temperature power electronics.Based on the principle of transient liquid phase method, the Sn alloy particles in solder paste were optimized to be Sn/Ni mixed particles, and ultrasonic action was applied to realize the rapid prototyping of the joint, and the compound joint had good high temperature stability.The effects of Ni content in the filler metal and the ultrasonic power on the microstructure and properties of the joint were studied systematically.It was found that the size of Ni particles directly affected the wettability of solder and the microstructure of the joint, and the content of Ni3Sn4 in the joint increased with the increase of Ni in the filler metal.When the welding temperature is 250 鈩，

本文编号：1763690