跨尺度、快速、三维激光直写光刻的规律与关键技术研究

Laser direct-writing photolithography is a micro-processing technology that the effective graphic windows and functionalization patterns on the substrate surfaces and media layers coated by photoresist were produced by the consecutive procedures of focused and high-precision laser beam (controlled by a computer) direct-writing exposure, development and chemical etching. . In this project, basing on the systematical study of the regularity and key technology including the matching of the photoresist and substrate, the photoresist film thickness uniformity on three-dimensional (3D) curved surfaces, and the line/space (L/S) resolution, precision, and stitching of the lithographic patterns on the 3D curved surfaces, trans-dimension, high-speed and 3D laser direct-writing photolithography will be realized. During this process, a 355-nm wavelength ultraviolet (UV) laser will be employed as the direct-writing exposure light source, the epoxy resin-glass fiber composite materials coated by copper foil will be selected as the substrate, and the the synchronization combination of a high-speed digital galvanometer scanner system, a dynamic focusing optical system and an x-y-z three-dimensional workstation will be implemented. Also, the differences of the mechanism and effectiveness between the laser direct-writing photolithogaphy, conventional optical photolithography, and laser direct etching will be explored.. This is a fabrication and processing technology of masklessness, high flexibility, high efficiency, and with a great industrialization and national defence application potential. If the project is realized, the great practical application value will be acquired, and the interaction mechanism of laser and photosensitive matter must be better understood.

激光直写光刻技术是指将计算机控制的高精度的激光束聚焦到涂覆有光刻胶的基材表面或介质层上，进行直接扫描曝光，之后经过显影和化学蚀刻等步骤，形成有效图形窗口或功能图形的一种精密微细加工技术。本申请项目拟通过对激光直写光刻过程中，光刻胶与基材的匹配性、三维曲面上光刻胶膜厚度涂覆均匀性、三维曲面直写光刻图形的线/间距分辨率、精度和拼接等规律与关键技术的系统研究，可望利用输出波长为355nm的紫外激光，在环氧树脂玻璃纤维-铜箔复合材料三维工件表面，与高速数字扫描振镜系统、动态聚焦光学系统和x-y-z三维工作台协同配合，实现跨尺度、快速、三维激光直写光刻，并与传统的光学光刻技术和激光直接蚀刻技术的机理与效率进行对比。这是一种无需掩膜、柔性化程度高、加工效率高、且具有巨大工业化和国防应用潜力的加工技术。项目的开展，既具有重要的实际应用价值，又能加深和拓宽对激光与感光材料相互作用机理的认识。

激光直写光刻技术是指将计算机控制的高精度的激光束聚焦到涂覆有光刻胶的基材表面或介质层上，无需掩膜，直接进行扫描曝光，之后经过显影和化学蚀刻等步骤，形成有效图形窗口或功能图形的一种精密、微细、智能加工技术。本项目系统地研究了激光三维直写光刻的规律和关键技术，并对激光三维直写光刻的材料、机理、工艺和实际应用进行了深入探讨..以重氮萘醌磺酸酯为感光剂、以高玻璃化温度的酰胺-酰亚胺共聚物为成膜树脂，制备了一种低成本、耐高温的紫外正型光刻胶，该光刻胶的相关性能（如线宽/线间距分辨率（可达1 μm）、曝光阈值能量密度（16 mJ/cm2）、润湿性等）可满足大幅面激光直写光刻使用要求，其曝光-显影-成像机理是基于光化学反应和溶解抑制机理；通过对旋涂时凸曲面上光刻胶的受力作用分析和合理假设，建立了光刻胶在三维凸曲面上的旋涂膜厚分布模型；.通过高斯光束的能量分布模型和Lambert定律，建立了激光直写光刻的能量密度分布和光刻图形轮廓的理论模型。结果表明，光刻胶对355 nm的紫外激光有较强吸收（吸收系数约为1.314 μm-1）；当胶层厚度较小时，光斑边缘的能量决定了其底层光刻半径；而当胶层厚度较大时，光斑中心的能量决定了其底层光刻半径。而离焦量、激光入射角度及动态聚焦均能影响入射至光刻胶表面激光光斑大小和形状，从而影响曝光能量密度的分布和光刻轮廓；光斑的变化是影响光刻图形尺寸精度的重要因素。.实际实验表明，相对于传统的平面光刻技术、激光直接刻蚀技术和柔性膜转移技术等，利用激光三维直写光刻技术，制备大幅面、大曲率的微细图形及频率选择表面等，具有效率高、精确度高和性能好等明显优点。因此，本论文研究的激光三维直写光刻技术对大幅面、大曲率三维曲面的跨尺度精密图形制作有巨大的应用前景。