基于飞秒激光微加工的三维金属微纳结构制备方法基础研究

3D metallic micro- and nanostructures have been of particular importance in Lab-on-chip, MEMS/NEMS, microelectronics, optoelectronics, chemistry and sensing. However, fabrication methods and technologies of such structures especially the true three dimensional metallic micro- and nanostructures still remains a great challenge. In this project, a new route is proposed to fabricate the three dimensional micro- and nanostructures via the femtosecond laser microprocessing and metal microsolidifying process. The microscopic transient mechanism of laser energy absorption, conduction, material ionization and modification during femtosecond laser processing the micro zone will be studied in the project. Then precise control of the interaction of light with matter will be carried out to realize the activation of chemical bonds and target modification of the modified area by femtosecond laser. The mechanism of high precision chemical etching of the femtosecond laser modified zone inside the bulk material will be proposed. And the new technology of true three dimensional micro- and nanostructures with high-aspect-ratio will be proposed. Meanwhile, special effort will be paid to explores the viscosity, fluidity and thermal strain characteristics and microscopic forming mechanism of metal materials with different physical properties after high temperature liquefaction inside the three dimensional microand nanostructures, and develop a high quality metal microsolidifying process. Finally, it will be gradually opened up new high precision methods and technologies for true three dimensional metallic micro- and nanostructures based on femtosecond laser micromachining in the project.

三维金属微纳结构由于其独特的导电、导热、电磁、光子和传感特性，在微流控芯片、微/纳机电系统、微电子、光电子、化学和传感等领域均有着十分重要的应用前景，但目前国际上仍非常欠缺有效制备三维金属微纳结构的方法。本项目针对三维金属微纳结构制备的难题，提出了一种基于飞秒激光微加工与金属微固化的三维金属微纳结构制备新方法。通过研究飞秒激光作用微区的激光能量吸收、传导、材料电离以及改性的微观瞬态机理，精确调控光与物质相互作用，实现飞秒激光作用中材料吸收光子能量对化学键的激活和目标改性，研究体材料内部飞秒激光改性区的高精度化学刻蚀机理和工艺，探索出大深宽比真三维微纳结构的加工方法与工艺，制备出适合金属微固化的超精细三维微纳结构；同时探究不同物理特性金属材料高温液化后在三维微纳结构内的流动性、粘滞性、热应变特性和微观成型机理，探索高质量的金属微固化方法与技术，发展和形成一种高精度三维金属微纳结构制备新方法。

本项目旨在探索一种基于飞秒激光微加工和金属微固化的三维金属微纳结构制备新方法。通过本项目的研究，发展出了一种新型超快成像方法，研究并澄清了飞秒激光对材料的靶向改性机理与激光改性区的化学湿法刻蚀机理，实现了材料内部的三维微纳结构的高效高精度制备，研究发展出了一种高效、高质量三维金属微固化新工艺。提出并完善了基于飞秒激光微加工的三维金属微纳结构制备的方法。成功制备出了多种典型三维金属微纳器件，包括三维微变压器、微加热器、PCR微流控集成芯片等，相关技术指标和器件特性达到国际同类器件的领先水平。项目执行期间，共在国际学术期刊上共发表了65篇SCI学术论文，发表中文期刊研究论文6篇，其中12篇论文被选为封面文章；申请相关发明专利18项。研究成果被《nature》、美国物理学会APS官网、美国光学学会OSA官网、美国光学工程学会SPIE官网、英国皇家化学学会RSC官网、《科技日报》、基金委网站等多次进行专题新闻报道。研究成果入选2019年中国光学十大进展和2019年中国光学十大新闻。项目执行期间做国际国内学术会议大会和邀请报告12次,6次担任专题会议主席。