SU-8胶双光子微加工分辨率与工艺条件研究

Resolution of SU-8 Photoresist in Two-Photon Polymerization Microfabrication and Research of Fabrication Conditions

为了提高SU-8光刻胶的微加工分辨率,利用飞秒激光双光子聚合技术研究了SU-8光刻胶微加工时的加工工艺条件与分辨率之间的关系。实验在本研究组自主研制的纳米光子学超细微加工系统上进行,以钛蓝宝石飞秒激光器发出的780nm波长激光作为加工光源,考察了不同激光功率与曝光时间等激光加工条件和后烤与无后烤等工艺条件对SU-8聚合点形貌与尺寸的影响。在后烤工艺条件下获得的最小加工点直径为0.22μm,而无后烤过程的加工结果中这一数值为0.47μm。实验结果表明,降低激光功率和缩短曝光时间可以获得尺寸较小的聚合点,后烤工艺有利于降低加工能量并提高加工分辨率,实验结果与基于双光子聚合加工理论的模拟分析具有良好的一致性。

In order to improve the microfabrication resolution of the SU-8 photoresist, the relationship between the fabrication conditions and resolution of the SU-8 photoresist was investigated by two-photon polymerization microfabrication technique. The two-photon polymerization experiments were performed on an own-made two-photon fabrication system through a Ti ： Sapphire femtosecond laser with the wavelength of 780 nm as the light source. The conditions influences of the laser power, exposure time, post-baking and without post-baking on the profile and size of SU-8 polymer spots were studied. The minimum diameter of the fabricated dots is 0. 22 μm on the condition of the post-baking process, but is 0.47μm without the post-baking process. The experimental results show that the polymer spots with the smaller size can be achieved by the lower laser power and shorter exposure time, and the post-baking process is advantaged to reduce fabricating laser power and improve the resolution. The experimental results have a good agreement with the simulated analysis based on two-photon polymerization microfabrication theory.