【作者】 刘中元；

【导师】 李金环； 刘华；

【作者基本信息】 东北师范大学 ， 光学， 2019， 硕士

【摘要】 近年来,随着芯片集成度的不断提高,基于数字微镜器件(DMD,Digital Micromirror Device)的新型无掩膜光刻技术受到人们的普遍关注。DMD具有响应时间短、分辨率高以及光学效率高等优点。DMD光刻技术降低了传统光刻技术在制作和加工掩膜版方面的困难和成本,使光刻技术繁琐的工艺流程得以简化,提高了光刻机的工作效率。匀光系统作为光刻机中的重要组件,是必不可少的。激光直接发出的光强通常是不均匀的,这种不均匀的光直接入射在DMD上进行光刻会造成刻写线宽与图案分辨率不一致,影响光刻效果。微透镜阵列是一种常见的匀光系统,但在应用于DMD光刻机时存在一些问题:首先,由于传统微透镜阵列中的子透镜采取周期排列的方式,在对相干光匀化时会出现比较明显的干涉条纹,影响匀光效果;其次,传统微透镜阵列匀光系统包含组件较多、占用体积大、难于集成;最后,在DMD光刻机中,DMD与主光轴光轴的垂面成24°,传统微透镜阵列匀光系统在与主光轴不垂直的方向不能获得均匀性较好的光斑。本文围解决绕传统微透镜阵列匀光系统应用于DMD光刻机的这些不足之处展开深入的研究,并且提出相应的解决方案:(1)本文针对传统微透镜阵列匀光系统对相干光进行匀化出现的干涉条纹问题提出随机微透镜阵列匀光系统,通过将子透镜位置随机分布的方式打破传统微透镜阵列的周期性,扰乱匀化光斑上的干涉条纹,提高匀光系统对相干光的匀化效果。(2)本文针对传统微透镜阵列难于集成的问题提出一种自由曲面微透镜阵列匀光系统。该匀光系统只包含一片自由曲面微透镜阵列,很大程度上减小匀光系统的组件数目,使系统集成更加容易;自由曲面微透镜阵列中的每一块子透镜都是通过能量映射法单独设计而成,在与光轴不垂直的方向得到照度比较均匀的光斑;通过随机设计每块子透镜尺寸的方式,解决对相干光匀化时会出现的干涉条纹问题。更多还原

【Abstract】 In recent years,with the continuous improvement of chip integration,new maskless lithography technology based on digital micromirror devices(DMD)has received widespread attention.DMD has the advantages of high resolution,high optical efficiency and short response time.DMD lithography technology reduces the difficulty and cost of traditional lithography in the fabrication and processing of masks,simplifies the tedious process of lithography,and improve the working efficiency of the lithography machine.The homogenizer is essential as an important component in the lithography machine.The light intensity of the light directly emitted by the laser is usually non-uniform.Non-uniform light directly illuminating on the DMD for lithography will result in inscribed line width and inconsistent resolution,which seriously affects lithography quality.The microlens array is a common homogenizing system,but they also have some problems when applied to DMD lithography machines.Firstly,the interference patterns on the DMD are obvious and regular because of the periodic structure of microlens array(MLA)and the coherence of the laser;Secondly,Due to its excessive number and volume of the components,it is difficult to integrate;Finally,because DMD is in the direction not perpendicular to the optical axis of the beam homogenize but is 24° to the vertical plane of its vertical plane,the uniformity is poor.In this paper,the shortcomings of the traditional microlens array homogenizing system applied to the DMD lithography machine are studied in depth,and the corresponding solutions are proposed:(1)In view of the interference patterns problem caused by the traditional microlens array for coherent light,a random microlens array is proposed.The periodicity of the sublens position is randomly distributed to break the periodicity of the traditional microlens array.The interference patterns of the target surface are disturbed,and the homogenization effect of the homogenizer for the coherent light is improved.(2)A novel freeform surface microlens array is proposed for the difficulty of integration of traditional microlens arrays.Such a beam homogenizer contains only one freeform microlens array(rfMLA),which minimize the number of components in the system and make system integration easier.And the rfMLA consists of different freeform microlenses.By the individual design of the sublens,efficient and uniform beam shaping results have been obtained in the direction not perpendicular to the optical axis of the beam homogenizer.By randomly designing the size of each sub-lens,the problem of interference patterns for the coherent light is solved.更多还原