步进式旋转光刻制备柱面微结构光栅模具

Fabrication of the Grating Mold with Micro-Patterns on the Cylindrical Surface by Step Rotating Lithography

相对于常规光栅制造方法 (如机械刻划和光学曝光等工艺)而言,连续辊压印技术更易实现低成本、连续和高效的大面积制造。高精度栅结构辊压印圆柱辊模具的制备工艺技术是连续辊压印技术实现高精度光栅复制的关键技术。针对这一问题提出了一种步进式旋转光刻工艺路线,将小区域的微结构光栅掩模通过步进式拼接曝光方式实现模具表面整周完整光栅的曝光。区别于传统平面曝光过程,筒形模具曲面曝光采用步进式旋转光刻工艺,其关键技术是:搭建高步进精度的旋转曝光工艺实验平台、解决筒形模具外径及光栅周期匹配问题和优化接近式拼接曝光工艺中的曝光间隙。通过理论分析和实验验证,得出了优化的步进旋转角度、筒形模具外径、光栅周期和接近式曝光间隙的条件,通过此工艺完成了柱面模具表面周期为20μm级的光栅结构的制备,为采用辊压印技术实现低成本、连续和高效大面积光栅制造创造了有利条件。

Compared with conventional grating manufacturing methods （i. e. mechanical machi- ning process and optical exposure process）, continuous roller imprinting is preferred to achieve low-cost, continuous and efficient manufacturing on large-area. One of the key challenges for roller imprinting is the fabrication of grating roller mold with continuous high-accuracy micro- structures over the whole cylindrical surface. To this point, a step rotating lithography process was proposed, in which continuous grating structures over the whole cylindrical surface were achieved by step splicing lithograph with the grating mask with small region microstructures. In contrast to the conventional lithography on planar surfaces, the exposure on the surface of the cy- lindrical mold takes use of the step rotating lithograph. The key technologies are to set up the platform for the step rotating lithography with high-accuracy rotating control, solve the match problem between the cylinder mold diameter and the grating period, and optimize the exposure gap in the proximity splicing lithography. With the theoretical analysis and experimental verification, the optimizations of the step rotating angle, cylindrical mold diameter, grating period and condition of the proximity exposure gap were obtained. By this novel process, a grating mold with high-accuracy 20μm-peroid grating structure over the whole cylindrical surface was fabrica- ted. The process creates favorable condition for realizing the large-area grating manufacturing with low-cost, continuous and efficient by roller imprinting technology.