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采用波长为355 nm的纳秒紫外重复脉冲激光对单晶硅片进行了盲孔加工实验,观测了随脉冲增加激光烧蚀硅片的外观形貌和盲孔孔深、孔径的变化规律,并对紫外激光辐照硅片的热力学过程进行了分析.研究结果表明:紫外激光加工硅盲孔是基于热、力效应共同作用的结果,热效应会使得硅材料熔化、气化甚至发生电离产生激光等离子体,为材料的去除提供条件;激光等离子体冲击波以及高温气态物向外膨胀会对熔化材料产生压力致使其向外喷射,为重复脉冲的进一步烧蚀提供了条件;力效应主要沿着激光传输的方向,垂直于硅表面,使得去除部位主要集中在孔的深度方向,达到较高的孔径比,实验观察孔径比可达8:1;此外,激光等离子体的产生也阻止了激光对靶面的作用,加之随孔深的增加激光发生散焦,使得烧蚀深度有一定的限制,实验观察烧蚀脉冲个数在前100个时加工效率较高.
Single-crystal silicon wafers were blind-hole processed with nanosecond repetitive pulsed laser at a wavelength of 355 nm. The appearance of the laser-ablated silicon wafers with increasing pulse width and the variation of hole depth and diameter were observed. The results show that the UV laser processing of the blind holes is based on the combined effect of thermal and force effects, and the thermal effect will cause the silicon material to melt, vaporize or even ionize to generate laser plasma Which provides the conditions for material removal. The laser plasma shock wave and the outward expansion of high-temperature gaseous materials will cause the molten material to generate pressure and cause it to jet outwards, which provides the conditions for further ablation of repeated pulses. The force effect is mainly transmitted along the laser Perpendicular to the silicon surface, making the removal of the site mainly in the depth direction of the hole to achieve a higher aperture ratio, the experimental observation of the aperture ratio up to 8: 1; In addition, the laser plasma also prevents the laser on the target surface In addition, as the depth of the hole increases, the laser defocusing causes the ablation depth to be limited. The number of ablation pulses experimentally observed in the first 100 hours Higher rates.