LGA焊盘设计对焊盘可焊性的影响探究  

Research on the influence of LGA pad design on solderability

作　　者：单海丹 迟美慧 姜博 禹业飞 Chan Haidan;Chi Meihui;Jiang Bo;Yu Yefei

机构地区：[1]广州广芯封装基板有限公司,广东广州510000

出　　处：《印制电路信息》2024年第S02期119-125,共7页Printed Circuit Information

摘　　要：本文针对栅格阵列封装(Land Grid Array,LGA)焊盘设计的可焊性进行了深入探究,旨在填补现有研究中对焊盘可焊性后失效产品在SMT工艺中焊接表现的认知空白。研究采用了不同尺寸的表面贴装器件焊盘(Surface Mount Device,SMD)和非阻焊定义焊盘(NonSolder Mask Defined,NSMD),并通过标准化可焊性测试方法,分析了它们的上锡效果。实验结果显示,在同等加工条件下,随着焊盘尺寸的增加,SMD焊盘的上锡率有所提高,但仍存在上锡不良的情况。相比之下,NSMD焊盘在相同尺寸下展现出更优越的可焊性,特别是在焊盘尺寸达到0.12 mm以上时,NSMD焊盘实现了完全的上锡率。这一发现强调了焊盘设计对焊接质量的关键作用,并提示在进行可焊性测试以评估产品焊接性能时,必须考虑到不同设计可能导致焊接表现的差异。另外,研究发现,某些可焊性不佳的焊盘在经过锡膏印刷补焊后,其上锡效果明显增强,这可能与液态锡的表面张力有关。这一观察提供了一种有效的验证方法:面对焊盘可焊性问题时,可通过锡膏印刷补焊来进一步检验焊盘的真实焊接能力。如果补焊成功,表明焊盘的焊接性能正常;反之,则需对焊盘设计或加工工艺进行调整优化。This study delved into the solderability of land grid array(LGA)pad designs with the aim of filling the knowledge gap regarding the soldering performance of post-solderability failure products in surface mount technology(SMT)processes.The research employed pads of various sizes from surface mount devices(SMDs)and non-solder mask defined(NSMD)pads,analyzed their tinning effects through standardized solderability testing methods.Experimental results indicated that under identical processing conditions,the tinning rate of SMD pads increased with the size of the pads;however,poor tinning still occurred.In contrast,NSMD pads exhibited superior solderability at the same sizes,particularly when the pad size exceeded 0.12 mm,achieving a complete tinning rate.This finding underscored the critical role of pad design in soldering quality and suggested that when conducting solderability tests to assess product soldering performance,it was imperative to consider the differences in soldering behavior that may result from varying designs.Additionally,the study found that the tinning effect of certain poorly solderable pads was significantly enhanced after solder paste printing rework,which may be related to the surface tension of liquid tin.This observation provided an effective validation method:when the pad showed poor solderability in liquid tin furnace,further examination of the actual soldering capability of the pads could be conducted through solder paste printing rework.If successful,it indicated normal soldering performance of the pads;otherwise,adjustments and optimization of the pad design or processing techniques were required.

关 键 词：LGA封装 焊盘设计 可焊性 锡膏印刷补焊 

分 类 号：TN41[电子电信—微电子学与固体电子学]