乙醇辅助激光烧蚀切割硅晶圆工艺

为了减小激光切割硅晶圆时的热效应，选择去离子水作为辅助液体进行激光切割实验，研究了水下切割时激光烧蚀激发气泡对硅片表面造成的不良影响。为解决水下激光切割进程中诱导气泡大面积粘结在硅片表面的问题，提出了去离子水混入乙醇溶液的实验方案，分析了水下激光切割中激光参数和乙醇浓度对切割质量的影响。实验结果表明，采用乙醇溶液作为辅助介质能明显减少粘结气泡的数量，减轻气泡破溃冲击带来的负面影响。实验采用乙醇浓度5 wt.%时切割得到的硅片比纯水中切割得到的硅表面影响区减小50%以上、切缝宽减幅约20%，有效提升了激光切割质量。

Process on ethanol assisted laser ablation dicing of silicon wafer

In order to reduce the thermal effect of laser dicing of silicon wafer, deionized water was used as assistant liquid to dice the silicon wafer. However, bubbles was induced during laser ablation and led to adverse effects on surface of silicon underwater dicing. Ethanol was mixed into deionized water to decrease the number of bubbles adhering on the surface of silicon which generated during the underwater laser dicing process. The impact of laser parameters and ethanol concentration on dicing quality were analyzed. The results of experiment show that the usage of ethanol as the assistant medium can decrease the number of bubbles adhering on the surface of silicon and alleviate the negative effect of bubble collapse. The kerf width decreases by 20% and the area of affected zone decreases by more than 50% when diced in an ethanol concentration of 5 wt.% compared to when diced in pure water. The dicing quality is improved effectively.