中国激光, 2015, 42 (9): 0910001, 网络出版: 2015-09-06
基于二维Ronchi光栅的纳米光刻对准技术研究
Lithography Alignment Technology Based on Two-Dimensional Ronchi Grating
傅里叶光学 二维光栅 光刻对准 叠栅条纹 频谱 Fourier optics two dimensional grating lithography alignment moiré fringe spectrum
摘要
提出了一种基于二维光栅叠栅效应的纳米光刻对准方法,用于接近式光刻实现二维同步对准。该方法采用两组周期接近的二维光栅重叠产生一组周期分布的叠栅条纹,条纹的周期相对于两光栅周期被大幅度放大,将光栅间的位移反应在条纹的相位信息中。利用二维光栅在傅里叶频谱中x、y 向相互独立的频谱分布,通过傅里叶变换对正交叠栅条纹横纵两个方向上的相位信息进行解析,可实现高精度二维同步对准。建立了双二维Ronchi光栅对准复振幅分布物理模型,推导了基片、掩模相对位移量与叠栅条纹相位之间的关系。通过计算机模拟对该对准方法进行了仿真分析,考虑噪声情况下,对准精度可以达到2 nm;通过实验系统对该对准方法进行测试,实验结果对准精度可以达到22 nm。
Abstract
A kind of nanometer lithography alignment method for two dimensional (2D) synchronization alignment in proximity lithography is presented. This method is based on the moiré effect. Two superposed 2D gratings with slightly different periods are adopted to generate a set of periodic moiré fringes, the period of which is hugely magnified with regard to that of two gratings and the relative displacement of gratings is encoded in the phase of fringes. Using the independent spectrum distribution of x and y direction in the Fourier spectrum and parsing the phase information on the transverse and longitudinal of moiré fringe by Fourier transformation can realize two dimensional high precision synchronization alignment. A kind of complex amplitude distribution model about two Ronchi 2D gratings alignment is built. Then, the relationship between the offsets of substrate and mask with moiré fringe is derived on the basic of this model. A simulation analysis about built model using computer is performed. The result shows that the accuracy can reach 2 nm when noise is considered; an experiment is made to test this alignment method after numerical computation. The accuracy of the result can reach 22 nm.
司新春, 佟军民, 唐燕, 胡松, 刘俊伯, 李金龙, 周毅, 邓钦元. 基于二维Ronchi光栅的纳米光刻对准技术研究[J]. 中国激光, 2015, 42(9): 0910001. Si Xinchun, Tong Junmin, Tang Yan, Hu Song, Liu Junbo, Li Jinlong, Zhou Yi, Deng Qinyuan. Lithography Alignment Technology Based on Two-Dimensional Ronchi Grating[J]. Chinese Journal of Lasers, 2015, 42(9): 0910001.