基于铜铟微纳米层常温超声辅助瞬态固相键合技术

目的 采用针状形貌铜铟微纳米层和超声能量，在常温下实现键合互连，保证互连的可靠性，从而解决传统回流焊工艺因高温引发的高热应力、信号延迟加剧等问题。方法 将镀有铜铟微纳米层的基板表面作为键合偶，对键合接触区域施加超声能量和一定压力，实现2块铜铟基板的瞬态固相键合。用扫描电子显微镜、透射电子显微镜、X射线衍射(XRD)、焊接强度测试仪等分析键合界面处的显微组织、金属间化合物及剪切强度，并对键合界面进行热处理。结果 在超声作用和较小的压力下，铜铟微锥阵列结构相互插入，形成了稳定的物理阻挡结构。键合界面处的薄铟层在超声能量作用下，其原子快速扩散转变为金属间化合物Cu2In。Cu2In是一种优质相，具有良好的塑性，有利于提高互连强度。当键合界面铟层的厚度为250 nm，键合压力为7 MPa，键合时间为1 s时，获得了相对最佳的键合质量，同时键合界面孔洞消失。热处理实验结果表明，这种固相键合技术无需额外进行热处理，就能获得良好的键合强度。结论 铜铟微纳米针锥的特殊形貌及超声波能量的引入，使键合在室温条件下即可瞬间完成，键合质量良好，可以获得较小的键合尺寸。

Ultrasonic Assisted Transient Solid Phase Bonding Technology Based on Copper-indium Micro Nano Layer at Room Temperature

High density three-dimensional lamination technology is the development trend of electronic packaging technology. With the thickness and spacing of chips becoming smaller and smaller, in order to solve the problem of high thermal stress caused by high temperature and aggravating signal delay in traditional reflow soldering process, the work aims to adopt the needle shaped copper-indium micro nano layer and ultrasonic assistance to realize bonding and interconnection at room temperature to ensure the reliability of interconnection. Ultrasonic assisted bonding technology refers to the bonding of metals on both sides under the action of ultrasonic and pressure, which can realize the low-temperature bonding between chips in a very short bonding time. The bonding pressure is small. Compared with the traditional hot pressing bonding, it reduces the damage of hot pressing to the chip and improves the reliability of the package.