Thermal damage of silicon wafer in thermal cleaving process with pulsed laser and CW laser
Thermal damage of silicon wafer in thermal cleaving process with pulsed laser and CW laser
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DOI：
10.1117/12.644564
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发表时间：
2006-02
影响因子：
16.4
通讯作者：
K. Yamada;T. Ueda;A. Hosokawa;Y. Yamane;K. Sekiya
中科院分区：
文献类型：
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作者：
K. Yamada;T. Ueda;A. Hosokawa;Y. Yamane;K. Sekiya
激光切割技术是一种切割玻璃、硅、陶瓷等脆性材料的新方法。在这种干燥过程中，材料只受到激光照射产生的热应力的影响。因此，材料不会受到机械切割过程中常用的冷却液的污染，但会在受照射的表面造成热损伤。本文的目的是防止激光切割硅片过程中的热损伤。用脉冲激光和连续激光进行了解理实验。用研制的双色高温计测量了脉冲激光解理过程中裂纹扩展所需的温度。应力强度因子略高于断裂韧性的临界温度取决于脉冲频率、脉冲宽度、激光光斑扫描速度和材料性能。热应力分析也证实了温度的存在。在此基础上，针对Cd激光切割，设计了冷藏卡盘系统，减少了对工件的热损伤。该系统将工作台冷藏在水的冰点以下，材料通过材料与工作台之间的冰冻水固定在工作台上。在室温下硅片表面生成氧化硅时，冷藏夹头可以防止热损伤，提高解理轨迹的直线度和解理过程的可靠性。
The laser cleaving process is a new method to cut brittle materials such as glass, silicon and ceramics. In this dry process, the material is diced only by the thermal stress induced by the laser irradiation. Therefore, the material is not contaminated with the coolant generally used in the mechanical dicing process, but teh thermal damages are caused on the irradiated surface. The objective of this paper is the prevention of thermal damages in the laser cleaving process of silicon wafer. The cleavin experiments are conducted with pulsed ND:YAG laser and cw Nd:YAG laser. In the cleaving with pulsed laser, the temperature required for crack propagation is investigated by measuring with a two-color pyrometer developed. The critical temperature at which the stress intensity factor slightly exceeds the fracture toughness depends on the pulse frequency, the pulse width, the scanning velocity of laser spot and the material properties. The temperature is also confirmed by the thermal stress analysis. And then, for the cleaving with cd laser, a refrigerating-chuck system is developed to reduce the thermal damage of workpiece. The system refrigerates the working table below the freezing point of water, and the material is fixed on the table by the frozen water between the material and the table. While the silicon oxide is caused on the surface of wafer in the room temperature, the refrigerating-chuch can prevent the thermal damage and improve the linearity of the cleaving trajectory and the reliability of the cleaving process.