摘要
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。
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.The transient solid phase bonding of two copper indium substrates could be realized by applying ultrasonic energy and a certain pressure to the bonding contact area.The microstructure,intermetallic compounds and shear strength at the bonding interface were analyzed by scanning electron microscope,transmission electron microscope,X-ray diffraction(XRD),and the bonding interface was heat-treated.The copper cone structure was stable under the interaction of small ultrasonic insertion pressure and copper cone structure.Both sides of the bonding interface were copper micro nano needle cone arrays coated with indium,which made the preparation of the bonding process easier.Indium had good cold solderability.Under the action of ultrasonic energy,the thin indium layer at the bonding interface diffused rapidly and transformed into intermetallic compound Cu2In.Cu2In was a high-quality phase with good plasticity,which was conducive to improving the interconnection strength.The thermal stress caused by high temperature of the chip was avoided and the packaging reliability was improved.When the thickness of indium layer at the bonding interface was 250 nm,the bonding pressure was 7 MPa and the bonding time was 1 s,the best bonding quality was obtained,and the holes at the bonding interface disappeared.Heat treatment experiments showed that this solid phase bonding technology could obtain good bonding strength without additional heat treatment.Due to the special shape of Cu-In micro nano needle cone and the introduction of ultrasonic energy,the bonding can be completed in an instant and at room temperature.The bonding quality is good,and the smaller bonding size can be obtained.Compared with the previous bonding technology requiring harsh conditions such as high vacuum,high temperature and high surface flatness,this bonding technology has loose conditions,can obtain smaller bonding size,high efficiency and less energy consumption,which is in line with the trend of green packaging.
作者
肖金
翟倩
周艳琼
李武初
陈基松
王超超
XIAO Jin;ZHAI Qian;ZHOU Yan-qiong;LI Wu-chu;CHEN Ji-song;WANG Chao-chao(Guangzhou Huali College,Guangzhou 511300,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第12期312-319,共8页
Surface Technology
基金
广州市科技计划基础与应用基础研究项目(202102080571)
增城区科技计划(2021ZCMS11)。
关键词
金属材料
固相键合
铜−铟微纳米
键合强度
扩散
metal material
solid phase bonding
Cu-In micro nano
bonding strength
diffusion
