Research on fabrication method for floating structures using general photolithography with high versatility
Research on fabrication method for floating structures using general photolithography with high versatility
复制标题
DOI：
10.1088/1361-6439/ac2d9b
复制
发表时间：
2021-10
影响因子：
2.3
通讯作者：
M. Horade;K. Yamada;T. Yamawaki;M. Yashima
中科院分区：
文献类型：
--
作者：
M. Horade;K. Yamada;T. Yamawaki;M. Yashima
本研究报告了一种塑料微尺度结构的微细加工方法。虽然利用微电子机械系统(MEMS)深刻蚀技术可以制造悬臂梁等阶梯状形状，但其缺点是制造工艺复杂，仅对硅的利用有限。因此，在本研究中，为了解决上述问题，我们仅使用通用的光刻工艺就实现了具有高通用性的多级结构的制造。具体地说，它可以只使用MEMS工艺中经常使用的SU-8抗蚀剂和AZ抗蚀剂来制造。AZ抗蚀剂的优点是可以溶解在SU-8抗蚀剂的显影剂中，无论是曝光的还是不曝光的。因此，AZ抗蚀剂的牺牲层可以用SU-8显影剂实现，从而消除了对用于蚀刻二氧化硅的氢氟酸等危险化学品的需要。在此，我们通过预先考虑AZ抗蚀剂的厚度、在SU-8中进行刻蚀所需的时间以及所需的特性，得出了最佳工艺条件。基于这些最佳工艺条件，该结构可以仅悬浮在孔阵列被图案化的区域中。虽然已经报道了使用AZ抗蚀剂作为牺牲层和浮动SU-8的方法，但在本研究中，仅通过光刻就可以同时制作浮动和固定结构。因此，我们成功地制造了齿轮结构和MEMS传感器，这两种结构都具有浮动和固定结构。上述结构是由高度透明的SU-8在玻璃基板上制成的，因此，用显微镜很容易观察到它们。聚二甲基硅氧烷微通道之所以被广泛使用，是因为它们是透明材料，可以在显微镜下观察，并通过SU-8抗蚀剂的简单光刻制造，使非微制造专家能够进入这一领域。这些发现有可能为开发新的生化测试奠定基础，例如在显微镜下驱动的执行器和传感器。
This research reports a micro-fabrication method for plastic microscale structures. Although a stepped shape, such as a cantilever, can be fabricated by micro electro mechanical systems (MEMS) deep etching technology, its disadvantages include the complicated fabrication process and its limited utilization with silicon only. Therefore, in this study, with an aim to address the aforementioned problems, we have realized the fabrication of a multi-stage structure using just a general photolithography process with high versatility. Specifically, it can be manufactured using only SU-8 resist and AZ resist, which are often used in the MEMS process. The AZ resist has the advantage of dissolving in the developer of the SU-8 resist, whether exposed or non-exposed. Thus, the sacrificial layer of AZ resist can be implemented with the SU-8 developer, thereby eliminating the need for dangerous chemicals such as hydrofluoric acid, which is used to etch silicon oxide. Herein, we have derived the optimum conditions by considering in advance the thickness of the AZ resist, the time taken to be etched in SU-8, and the desired features. Based on these optimum processing conditions, the structure could be suspended only in the region where the hole array was patterned. Although methods of using AZ resist as a sacrificial layer and floating SU-8 have been reported, in this study, both floating and fixed structures could be simultaneously fabricated by photolithography only. Accordingly, we successfully manufactured a gear structure and a MEMS sensor, both of which have floating and fixed structures. The above structures are made of highly transparent SU-8 on a glass substrate; hence, they are easily observable with a microscope. The reason for the widespread use of polydimethylsiloxane micro-channels is that they are transparent materials that can be observed under a microscope and fabricated by simple photolithography of the SU-8 resist, enabling non-microfabrication specialists to enter this field. These findings have the potential to form the foundation for developing new biochemical tests, such as actuators and sensors driven under a microscope.