一种数字光栅无掩模光刻对准方法

A Digital-Grating-Based Alignment Technique in Maskless Lithography

针对数字微反射镜装置(DMD)无掩模光刻系统,提出并研究了一种数字光栅无掩模光刻对准方法,将硅片的微位移放大显示在数字光栅与硅片物理光栅叠加产生的叠栅条纹中。建立了基于DMD的数字光栅无掩模光刻对准模型,设计了对准标记以及具体的实现方案,并对模型进行了数值仿真和初步的实验验证。结果表明,采用频率可变、图像干净、具有良好周期性结构的数字光栅代替传统的真实掩模光栅,真正实现了零掩模成本;并且采用变频率数字光栅可以扩大测量范围,减小位移测量误差。最终可以实现深亚微米的对准精度,满足目前无掩模光刻对准精度的要求。

A digital-grating-based alignment technique is brought forward and researched for digital micromirror device（DMD） maskless lithography system.Infinitesimal displacement of a silicon chip is amplified and displayed in moiré fringes generated by digital grating and physical grating.A digital-grating-based alignment model is created in DMD-based maskless lithography system.The alignment marks as well as detailed realization program is designed.Numerical simulation and preliminary experimental test is carried out.Compared to the traditional real mask,the grating digital gating characterized with variable frequency,clear image,good periodic structure and zero mask cost will extend the measurement range and reduce the displacement measurement error.This technique can realize deep sub-micron alignment accuracy,and satisfy the requirements of maskless lithography.