In this paper, we present the development of a high-speed dual-beam stealth laser dicing (D-SLD) method for processing semiconductor wafers based on electrically tunable lenses (ETLs). An SLD system utilizes a laser beam to dice a wafer by inducing interior defects without modifying the surface characteristics of a wafer, thereby presenting significant advantages over conventional dicing methods, e.g., blade dicing or laser ablation. Currently, the throughput of SLD is limited by the serial scanning process; in addition, wafer misalignment and the warpage effects together deteriorate the dicing quality and yield and demand high-cost multi-axis precision stages. To address the issue, we parallelize the dicing process by splitting the laser focus into two foci, where the laser intensity at different depths are automatically adjusted to achieve optimal dicing condition. By combining the height sensor and ETLs, each laser focus, i.e., laser scan lines, can be rapidly controlled axially to compensate the wafer curvature and misalignment errors in real time, leading to substantially improved precision (kerf width < 2 μm) and speed, demonstrated by our experimental results. The new dual-beam laser dicing system presents an effective solution for high-speed wafer dicing as well as other important engineering applications, e.g., fabrication of micro-devices and optical components.

在本文中，我们介绍了用于处理基于电子可调透镜（ETL）的半导体晶圆的高速双光束隐形激光切割（D-SLD）方法的开发。SLD系统利用激光束通过引起内部缺陷而不改变晶片的表面特性来将晶片切成小片，从而相对于传统的切割方法，例如刀片切割或激光烧蚀，具有明显的优势。当前，SLD的吞吐量受到串行扫描过程的限制；另外，晶片的未对准和翘曲效应共同降低了切割质量和成品率，并需要高成本的多轴精密平台。为了解决这个问题，我们通过将激光焦点分为两个焦点来并行化切割过程，自动调整不同深度的激光强度，以达到最佳切割条件。通过结合高度传感器和ETL，可以轴向快速控制每个激光焦点（即激光扫描线），以实时补偿晶圆曲率和未对准误差，从而显着提高精度（切口宽度<2μm）和速度，由我们的实验结果证明。新的双光束激光切割系统为高速晶圆切割以及其他重要工程应用（例如微型设备和光学组件的制造）提供了有效的解决方案。通过我们的实验结果证明，可以显着提高精度（切缝宽度<2μm）和速度。新的双光束激光切割系统为高速晶圆切割以及其他重要工程应用（例如微型设备和光学组件的制造）提供了有效的解决方案。通过我们的实验结果证明，可以显着提高精度（切缝宽度<2μm）和速度。新的双光束激光切割系统为高速晶圆切割以及其他重要工程应用（例如微型设备和光学组件的制造）提供了有效的解决方案。