摘要
在倒装封装技术中,底部填充胶主要起到支撑、固定和缓解焊点热应力的作用,进而提升封装元件的使用寿命。然而,若底部填充胶选型或清洗工艺制程不合理,则将引起底部填充胶空洞率较高,从而导致封装产品失效。因此,以实际工程样品为基础,采用试验的方法研究对比了3种不同底部填充胶和清洗工艺(4步清洗工序)对底部填充胶空洞率的影响。结果表明,底部填充胶空洞率随底部填充胶黏度的增大而增大,当芯片下方焊点间距小于等于75μm时,底部填充胶在最佳点胶温度下的初始黏度不可超过0.11 Pa·s,可保证底部填充胶空洞率小于1%。清洗工艺中清洗液清洗工序对底部填充胶空洞率影响最大,水精漂循环和氮气风切干燥循环工序无明显影响,水溶性助焊剂对底部填充胶空洞率影响较小。空洞内部残留物为助焊剂和清洗液反应后的物质,其分布规律主要与Bump排列方式和间距有关。
In the context of the flip chip package technology,the underfill is used for support,fixing the solder joints,and alleviating the thermal stress,thereby enhancing the operation life of the packaged components.However,if the selection and cleaning process of the underfill are not conducted appropriately,it presents a high underfill void rate,which ultimately leads to the failure of the packaged products.In this study,we experimentally analyzed the effects of three different underfills and cleaning processes(four-step cleaning processes)on the underfill void rate based on the actual engineering samples.The results indicate that an increase in the viscosity of the underfill corresponds to an elevated underfill void rate.Furthermore,when the bump pitch under the die is less than 75μm,the initial viscosity of the underfill at the optimal dispensing temperature must be less than 0.11 Pa·s,which ensures that the underfill void rate lies below 1%.The cleaning agent exerts the most significant influence on the underfill void rate in the cleaning process,whereas the water precision bleaching cycle and nitrogen wind cutting-drying cycle have no discernible impact.The effect of the water-soluble flux on the void rate of underfills is relatively minimal.The residue within the voids is attributed to the reaction between the flux and cleaning agent.Its distribution is primarily influenced by the mapping and pitch of the solder joints.
作者
方劝程
李岚清
吴浩羽
曾维
钱程东
孙瑜
黄辰骏
王强
FANG Quancheng;LI Lanqing;WU Haoyu;QIAN Chengdong;SUN Yu;HUANG Chenjun;WANG Qiang(Phytium Technology Co.,Ltd.,Tianjin 300459,P.R.China;Chengdu Wanying Microelectronics Co.,Ltd.,Chengdu 611731,P.R.China;School of Integrated Circuit Science and Engineering,University of Electronic Science And Technology of China,Chengdu 611731,P.R.China)
出处
《微电子学》
北大核心
2025年第2期321-326,共6页
Microelectronics
基金
CCF-飞腾基金(CCF-Phytium202206)。
