The current trend of electrical devices development is progressing towards miniaturization, multi-function and high density, device integration and fine pitch in a smaller package size. This led to the invention of copper pillar bumps which acts as a connection between the dies to its corresponding substrate, which allows the fabrication of smaller semiconductor devices. The dies were mounted onto the substrate by undergoing mass reflow process where the SAC305 solder from the copper pillar bumps and substrate bumps will melt together and solidify to form a solder joint. The quality of the solder joint is influenced by the parameters that govern the reflow profile, which are ramp rate, soak time, time above liquidus time, peak temperature and cooling rate. If the reflow profile is not properly optimized, defects such as voids in the solder joint can pose a reliability issue for the packaged unit. Therefore, in this paper, ramp rate, soak time and time above liquidus of reflow profiles for die utilizing copper pillar bumps with SAC305 as its solder material was studied and optimized in finding the recommended range of each parameter of the reflow profiles that yield the least voiding in the solder joint. The experiment was conducted by varying the reflow profile parameter which are ramp rate, soak time and time above liquidus, which the solder joint cross section and X-ray images were then analysed to study its influences. Additional experiment that investigates flux outgassing rate of different flux activity levels and the influence of component standoff height and mis-alignment offset towards solder-creeping defect were conducted in this article.

目前电子器件的发展趋势是朝着小型化、多功能化、高密度化、器件集成化、小间距化、更小封装尺寸的方向发展。这导致了铜柱凸块的发明，它充当管芯与其相应基板之间的连接，从而允许制造更小的半导体器件。通过大量回流工艺将管芯安装到基板上，其中来自铜柱凸块和基板凸块的 SAC305 焊料将熔化在一起并凝固以形成焊点。焊点的质量受控制回流曲线的参数的影响，这些参数是升温速率、保温时间、液相线以上时间、峰值温度和冷却速率。如果回流温度曲线没有得到适当优化，焊点中的空隙等缺陷可能会对封装单元造成可靠性问题。因此，在本文中，研究并优化了以 SAC305 为焊接材料的铜柱凸块的回流焊曲线的升温速率、浸泡时间和液相线以上时间，以找到回流焊曲线的每个参数的推荐范围，从而使产量最小焊点中的空洞。通过改变回流温度曲线参数（升温速率、保温时间和液相线以上时间）进行实验，然后分析焊点横截面和 X 射线图像以研究其影响。本文还进行了额外的实验，研究不同助焊剂活性水平的助焊剂脱气率以及元件间距高度和未对准偏移对焊料蠕变缺陷的影响。