采用脉宽为10 ps、频率为200 kHz、波长为1064 nm的皮秒激光在硅表面扫描会自成形微孔结构，通过改变脉冲能量密度、扫描速度和扫描次数，实验研究了微孔的演变规律。结果表明：不同参数对微孔的影响可以归纳为脉冲能量密度和单位面积内有效脉冲数。随着脉冲能量密度的增加，微孔逐渐向沟槽两侧移动，由初始的随机排列演变成一维线性均匀排列；随着单位面积内有效脉冲数的增加，边缘两侧微孔数量由少变多，尺寸由小变大，最终消失。通过模拟温度场分析了不同温度下材料相变和表面张力的变化，发现在表面张力的驱动下液相硅凝固形成凸起，凸起导致激光能量不均匀沉积，最终形成微孔。这表明微孔自成形的物理机理为激光诱导材料相变和马兰戈尼效应的共同作用。

Scanning silicon surface with a picosecond laser with pulse width of 10 ps, frequency of 200 kHz and wavelength of 1064 nm will self-form microhole structure. By changing pulse energy density, scanning speed and scanning times, the evolution law of microhole is studied experimentally. The results show that the influence of different parameters on microholes can be summarized as pulse energy density and effective pulse number per unit area. With the increase of pulse energy density, the microholes gradually move to both sides of the groove, from the initial random arrangement to the one-dimensional linear uniform arrangement. With the increase of effective pulse number per unit area, the number of microholes on both sides of the edge changes from less to more, and the size changes from small to large, and finally microholes disappear. By simulating the temperature field, the change of phase transition and surface tension of materials at different temperatures was analyzed. It was found that liquid silicon solidified under the drive of surface tension to form protrusions, which led to uneven deposition of laser energy and finally formed microholes. This indicates that the physical mechanism of microhole self-forming is the combined action of laser-induced material phase transformation and Marangoni effect.