In this paper, the authors report a method for continuous trench micromachining on polymethylmethacrylate (PMMA). Visible laser-induced backside wet etching (v-LIBWE) on PMMA using a potassium permanganate (KMnO4)-based absorber liquid was studied. PMMA is widely used in microfluidic devices for chemical and biological applications. Conventional micromachining of channels in the PMMA substrate using CO2 lasers achieves the smallest feature of approximately 85 μm. In this study, a continuous 12 μm-wide trench etching on PMMA was achievable by v-LIBWE using a 532 nm nanosecond pulsed laser. The etching threshold is ∼10 J/cm2, which corresponds to the average power of 58 mW for the repetition rate of 10 kHz. The authors also determined that the lowest scanning speed of 2 mm/s was necessary for the v-LIBWE of PMMA to generate the crack-free surface. Our study provides a new perspective and a convenient approach for the micromachining of the polymer substrate using v-LIBWE.

中文翻译：

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使用可见光激光诱导背面湿蚀刻，以 KMnO4 溶液作为吸收剂，在聚甲基丙烯酸甲酯基板上进行表面微加工

在本文中，作者报告了一种在聚甲基丙烯酸甲酯 (PMMA) 上进行连续沟槽微加工的方法。研究了使用基于高锰酸钾 (KMnO4) 的吸收液在 PMMA 上进行可见激光诱导背面湿法蚀刻 (v-LIBWE)。PMMA 广泛用于化学和生物应用的微流体装置。使用 CO2 激光器对 PMMA 基板中的通道进行常规微加工可实现约 85 μm 的最小特征。在这项研究中，v-LIBWE 使用 532 nm 纳秒脉冲激光器在 PMMA 上实现了连续 12 μm 宽的沟槽蚀刻。蚀刻阈值为~10 J/cm2，对应于重复频率为 10 kHz 时的平均功率为 58 mW。作者还确定，2 mm/s 的最低扫描速度对于 PMMA 的 v-LIBWE 生成无裂纹表面是必要的。