飞秒激光微加工薄膜对于MEMS设备的制造是一个急需的技术。 文章使用波长为775 nm的Ti: sapphire飞秒激光器(脉宽约为130 fs, 频率为1 000 Hz)研究厚度为4 μm的Au薄膜, 在不同加工参数下的结构特性, 发现单脉冲消融时消融直径随着脉冲能量的增大而增大。 当单脉冲能量一定时, 消融直径随着脉冲的个数变化不大。 计算得到Au膜的单脉冲消融阈值为Ｆｔｈ＝0.7 J·cm-2, 使用脉冲能量略大于阈值时, 在薄膜上所划出的线为凸起状; 当超过阈值时所得直线为凹起状。 同时发现在脉冲能量一定时所得线宽随着加工速度的增加而减小; 当加工速度一定时线宽随着能量的增加而增大。

Femtosecond laser micromachining of film is an emerging technology for fabrication of MEMS devices. A Ti: sapphire laser (130 fs, 1 000 Hz)was used to irradiate the thin film with variations in process parameters such as pulse energy. The film thickness is about 4 μm which was measured by AFM. When we used single pulse to excite the film, the ablation diameter increased along with the energy ascending; when the energy of single pulse was invariable, the diameter had little change when altering the number of pulses. The single pulse threshold fluence of Au film was Ｆｔｈ＝0.7 J·cm-2 at this ultrashort pulse-length in air. By changing the energy of excitation pulse it was found that when the energy was lower than the threshold, the line on the film was heaved; when the energy was higher than the threshold, the line was concave, which was detected by AFM. It was also found that the width of line decreased along with the increase in process speed when the pulse energy remained unchanged; the width of line increased along with the pulse energy ascending when the process speed was fixed.