High-aspect-ratio three-dimensional polymer and metallic microstructure microfabrication using two-photon polymerization

IF 3 4区医学 Q3 ENGINEERING, BIOMEDICAL

Biomedical Microdevices Pub Date : 2023-07-29 DOI:10.1007/s10544-023-00665-z

Ethan Vargas, Can Huang, Zhiyu Yan, Harold White, Jun Zou, Arum Han

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引用次数: 1

Abstract

Creating micrometer-resolution high-aspect-ratio three-dimensional (3D) structures remain very challenging despite significant microfabrication methods developed for microelectromechanical systems (MEMS). This is especially the case when such structures are desired to be metallic to support electronic applications. Here, we present a microfabrication process that combines two-photon-polymerization (2PP) printing to create a polymeric high-aspect-ratio three-dimensional structure and electroless metal plating that selectively electroplates only the polymeric structure to create high-aspect-ratio 3D metallic structures having micrometer-resolution. To enable this, the effect of various 2PP processing parameters on SU-8 photoresist microstructures were first systematically studied. These parameters include laser power, slicing/hatching distances, and pre-/post-baking temperature. This optimization resulted in a maximum aspect ratio (height to width) of ~ 12. Following this polymeric structure printing, electroless plating using Tollens’ Reagent were utilized to selectively coat silver particles only on the polymeric structure, but not on the silicon substrate. The final 3D metallic structures were evaluated in terms of their resistivity, reproducibly showing resistivity of ~ 10^–6 [Ω·m]. The developed 3D metallic structure microfabrication process can be further integrated with conventional 2D lithography to achieve even more complex structures. The developed method overcomes the limitations of current MEMS fabrication processes, allowing a variety of previously impossible metallic microstructures to be created.

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使用双光子聚合的高纵横比三维聚合物和金属微结构微制造。

尽管为微机电系统（MEMS）开发了大量的微制造方法，但创建微米分辨率的高纵横比三维（3D）结构仍然非常具有挑战性。当期望这样的结构是金属的以支持电子应用时尤其如此。在这里，我们提出了一种微制造工艺，该工艺结合了双光子聚合（2PP）印刷以产生聚合物高纵横比三维结构和化学镀金属，化学镀金属选择性地仅电镀聚合物结构以产生具有微米分辨率的高纵横比3D金属结构。为了实现这一点，首先系统地研究了各种2PP工艺参数对SU-8光刻胶微观结构的影响。这些参数包括激光功率、切片/影线距离以及烘焙前/烘焙后温度。此优化导致最大纵横比（高宽比）为 ~ 12.在这种聚合物结构印刷之后，使用Tollens试剂的化学镀被用于选择性地仅将银颗粒涂覆在聚合物结构上，而不涂覆在硅衬底上。最终的3D金属结构根据其电阻率进行了评估，可再现地显示了 ~ 10-6[Ω·m]。所开发的3D金属结构微制造工艺可以与传统的2D光刻进一步集成，以实现更复杂的结构。所开发的方法克服了当前MEMS制造工艺的局限性，允许创建各种以前不可能的金属微结构。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Biomedical Microdevices 工程技术-工程：生物医学

CiteScore

6.90

自引率

3.60%

发文量

审稿时长

6 months

期刊介绍： Biomedical Microdevices: BioMEMS and Biomedical Nanotechnology is an interdisciplinary periodical devoted to all aspects of research in the medical diagnostic and therapeutic applications of Micro-Electro-Mechanical Systems (BioMEMS) and nanotechnology for medicine and biology. General subjects of interest include the design, characterization, testing, modeling and clinical validation of microfabricated systems, and their integration on-chip and in larger functional units. The specific interests of the Journal include systems for neural stimulation and recording, bioseparation technologies such as nanofilters and electrophoretic equipment, miniaturized analytic and DNA identification systems, biosensors, and micro/nanotechnologies for cell and tissue research, tissue engineering, cell transplantation, and the controlled release of drugs and biological molecules. Contributions reporting on fundamental and applied investigations of the material science, biochemistry, and physics of biomedical microdevices and nanotechnology are encouraged. A non-exhaustive list of fields of interest includes: nanoparticle synthesis, characterization, and validation of therapeutic or imaging efficacy in animal models; biocompatibility; biochemical modification of microfabricated devices, with reference to non-specific protein adsorption, and the active immobilization and patterning of proteins on micro/nanofabricated surfaces; the dynamics of fluids in micro-and-nano-fabricated channels; the electromechanical and structural response of micro/nanofabricated systems; the interactions of microdevices with cells and tissues, including biocompatibility and biodegradation studies; variations in the characteristics of the systems as a function of the micro/nanofabrication parameters.