用于无模光刻的连续浮雕谐衍射透镜阵列设计

Design of continuous-relief harmonic diffractive microlens array for maskless lithography

为了获得实时调焦写入以及高的系统分辨力和衍射效率,提出了一种基于连续浮雕谐衍射透镜阵列的无模光刻方法。该方法采用连续浮雕谐衍射透镜阵列作为无模光刻的物镜阵列,在兼顾系统分辨力和衍射效率基础上,由同一衍射透镜阵列实现聚焦写入和检焦;同时利用谐衍射透镜的深浮雕特性调制透镜的环带宽度,降低透镜的制作难度。在分析谐衍射透镜特点以及考虑激光直写制作工艺对连续深浮雕衍射聚焦特性影响的基础上,设计、制作并测试了设计波长为441.6nm,F数为7.5的连续浮雕谐衍射透镜阵列。测试结果表明,该阵列同时具有聚焦写入和检焦功能,且对写入激光和检焦激光的衍射效率均优于70%,有望改善无模光刻的制作质量。

In order to achieve the focusing in real time and to obtain the high writing resolution and diffraction efficiency in the exposure process,a new maskless lithography based on a continuous-relief harmonic diffractive microlens（DMs）array is proposed.The lithography takes the continuous-relief harmonic diffractive microlens array as an objective array of the maskless lithography to integrate the defocus-detecting array and the writing array by taking both the writing resolution and diffraction efficiency into consideration,and to design the array with a deep relief to make the array fabrication easy.To verify its validity,the continuous-relief harmonic diffractive microlens array with F/7.5 and a design wavelength of 441.6 nm is designed,and fabricated after analysis on the characteristics of maskless lithography.Experimental results indicate that the developed array can be used to synchronously focus the writing laser and the autofocusing laser into the same spots,and can achieve a diffraction efficiency over 70% for both writing wavelength and defocus-detecting wavelength.