Belle Stefan, Goetzendorfer Babette, Hellmann Ralf
Applied Laser and Photonics Group, Aschaffenburg University of Applied Sciences, Wuerzburger Str. 45, 63743 Aschaffenburg, Germany.
Materials (Basel). 2020 Nov 22;13(22):5279. doi: 10.3390/ma13225279.
We report on the challenges in a hybrid sub-micrometer fabrication process while using three dimensional femtosecond direct laser writing and electroplating. With this hybrid subtractive and additive fabrication process, it is possible to generate metallic polarization elements with sub-wavelength dimensions of less than 400 nm in the cladding area. We show approaches for improving the adhesion of freestanding photoresist pillars as well as of the metallic cladding area, and we also demonstrate the avoidance of an inhibition layer and sticking of the freestanding pillars. Three-dimensional direct laser writing in a positive tone photoresist is used as a subtractive process to fabricate free-standing non-metallic photoresist pillars with an area of about 850 nm × 1400 nm, a height of 3000 nm, and a distance between the pillars of less than 400 nm. In a subsequent additive fabrication process, these channels are filled with gold by electrochemical deposition up to a final height of 2200 nm. Finally, the polarization elements are characterized by measuring the degree of polarization in order to show their behavior as quarter- and half-wave plates.
我们报告了在使用三维飞秒直接激光写入和电镀的混合亚微米制造工艺中所面临的挑战。通过这种混合的减材和增材制造工艺，可以在包层区域生成亚波长尺寸小于400纳米的金属偏振元件。我们展示了提高独立光刻胶柱以及金属包层区域附着力的方法，并且还演示了如何避免抑制层和独立柱的粘连。在正性光刻胶中进行三维直接激光写入作为一种减材工艺，用于制造面积约为850纳米×1400纳米、高度为3000纳米且柱间距小于400纳米的独立非金属光刻胶柱。在随后的增材制造工艺中，通过电化学沉积用金填充这些通道，最终高度达到2200纳米。最后，通过测量偏振度对偏振元件进行表征，以展示它们作为四分之一波片和半波片的性能。
