聚焦开发清晰、无飞溅、无碎屑且深度满足半导体晶圆后道加工工序要求的激光标识工艺, 实现清晰可辨、高洁净度的硅晶圆激光标识。采用波长532 nm的激光器研究平均功率、脉冲重复频率和扫描速度等激光工艺参数对晶圆标识质量的影响, 借助目视、显微镜和白光干涉三维轮廓仪来评估标识码的清晰程度、标识点的深浅程度和隆起高度以及热影响区。研究表明, 在低脉冲频率小于50 kHz时, 随着平均功率的上升, 标识码的清晰度逐渐增加, 但是硅渣的数量及其分布区域增大; 在高脉冲频率大于60 kHz时, 平均功率增加对标识码清晰度的影响及硅渣数量和分布区域的变化没有低频段表现明显。在平均功率为20%, 脉冲重复频率为60~80 kHz, 扫描速度为2 500~3 500 mm·s-1的工艺窗口内可以优化参数组合, 在硅晶圆上实现清晰可辨、无飞溅和碎屑污染, 字体深度为0.5~5 μm并且隆起小于1 μm的激光标识。

To realize the laser marking of Si wafers with clear identification and high cleanliness, this paper focuses on developing a laser marking process that is clear, splash free, debris free, and deep enough to meet the requirements of the subsequent processing process of semiconductor wafers. A 532 nm laser is used to study the influence of laser process parameters such as average power, pulse repetition frequency, and scan speed on laser marking of the Si wafer. The clarity, the depth, the height of the bump, and the heat affected zone of laser markings are evaluated by visual inspection, microscope, and white light interference three-dimensional profilometer. The research shows that compared with the low pulse frequency level below 50 kHz, the influence of average power and scan speed on the laser marking are lower. In the process window with average power 20%, pulse repetition frequency 60~80 kHz, and scan speed of 2 500~3 500 mm·s-1, parameter combination can be optimized to realize clear identification, no splash, and debris pollution laser marking on the silicon wafer, and the laser marking dots depth is 0.5~5 μm and the bump is less than 1 μm.