微水射流导引激光加工是一种热影响区小,具有高加工精度的新型技术。本文基于有限体积法建立了微水射流导引激光束对硅片打孔过程的传热模型,将打孔过程分为三个阶段模拟其间的热量传递、相变过程和相边界的移动;探索了微水射流导引双脉冲激光打孔过程,进行了双脉冲不同延迟时间下的传热过程的数值模拟,得到了最佳延迟时间。结果表明:在初始加热阶段,高温区出现在表面以下区域;微水射流有强冷却作用并明显减小了热影响区;双脉冲激光的应用可以有效提高打孔的效率。
Micro-waterjet guided laser processing is an advanced technique with the advantages of narrow heat affect zone and high precision.A heat transfer model and simulations based on the finite volume method(FVM) for micro-waterjet guided laser drilling silicon wafer are presented in this study.The whole drilling process is treated as three stages with heat transfer,phase changes and moving boundary simulated and analyzed in details.The dual-pulse laser guided by micro-waterjet for the drilling process is proposed and explored.From heat transfer analyses and numerical simulations, the higher processing efficiency is obtained with the optimal dual-pulse laser delay time.The results illustrate that during the initial heating stage a high-temperature region exists just below the surface, the high cooling effect performed by waterjet reduces heat affect zone,and the drilling efficiency can be enhanced by the adopt of dual-pulse laser.