QFN器件焊接缺陷分析与工艺优化  

Welding Defect Analysis and Optimization of QFN Package

作　　者：刘颖 吴瑛 陈该青[1] 许春停[1] LIU Ying;WU Ying;CHEN Gaiqing;XU Chunting(The 38th Institute of China Electronic Technology Corporation,Hefei 230088,China;Institute of Space Integrated Ground Network,Hefei 230088,China)

机构地区：[1]中国电子科技集团公司第三十八研究所,合肥230088 [2]天地信息网络研究院有限公司,合肥230088

出　　处：《电子与封装》2022年第1期18-22,共5页Electronics & Packaging

基　　金：高效率多波段抗干扰天线技术研究(61671416)。

摘　　要：QFN器件具有良好的电气性能,但器件回流焊接过程中极易产生底部热沉焊盘焊接空洞、器件引脚间锡珠、桥连等缺陷,当一个印制板焊接多个QFN器件时,缺陷发生率颇高。在高可靠性要求的航天产品焊接过程中,器件返修次数有限制,且返修会造成器件性能下降、组件可靠性降低等问题,因此亟需对QFN器件一次装配良率和焊接效果进行提升优化。为此,从原理上分析QFN器件热沉焊盘焊接空洞、器件引脚间锡珠缺陷产生机理,并从产品焊盘工艺性设计、钢网模板设计、焊接温度曲线设计等方面开展分析与优化。优化后,QFN器件一次装配良率提高,没有产生锡珠、虚焊等缺陷。QFN devices have good electrical properties,but weld defects such as hole,solder spatters,bridge connection are frequently occurred in the process of reflow welding.When multiple QFN devices are welded on one printed-circuit board,the occurrence rate of defects is quite high.In the welding process of aerospace products with high reliability requirements,repairing is limited,and the repair of electronic devices will decline electrical properties and reliability.Therefore,it is urgent to improve and optimize the primary assembly yield and welding effect of QFN devices.The mechanism of QFN device heat sink pad welding cavity and solder spatters is analyzed in principle,and optimization of solder pad design,steel mesh template design and welding temperature are carried out.Optimization have made a positive influence of QFN device soldering,and defect such as solder spatters and false welding are solved.

关 键 词：QFN 焊盘设计 钢网模板设计 焊接温度曲线 

分 类 号：TN454[电子电信—微电子学与固体电子学]