基于等效叠栅的反射式光刻对准模型研究  

Alignment Scheme Research Based on Equivalent Overlapped Gratings for Reflective Lithography Alignment

作　　者：朱江平[1,2,3] 胡松[1] 于军胜[2] 唐燕[1] 周绍林[4] 刘旗[1,3] 何渝[1,3] 

机构地区：[1]中国科学院光电技术研究所,四川成都610209 [2]电子科技大学光电信息学院,四川成都610054 [3]中国科学院研究生院,北京100049 [4]华南理工大学电子与信息学院,广东广州610540

出　　处：《中国激光》2012年第9期163-167,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(60976077;61076099)资助课题

摘　　要：针对接近接触式光刻技术的特点,提出了一种实用的反射式光刻对准方案。方案采用差动叠栅条纹对准技术,以叠栅条纹相位作为对准信号的载体。在掩模和硅片上分别设计两组位置相反、周期接近的光栅对准标记。电荷耦合器件(CCD)成像系统接收叠栅条纹图像,采用傅里叶变换提取叠栅条纹相位,得到掩模与硅片的相对位置关系。设计的标记可同时探测横纵方向的对准偏差。给出了合理的光路设计方案,详细分析了整个系统对准的内在机制,建立了可行的数学模型。研究表明,当对准偏差小于1pixel时,最大误差低于0.002pixel。与透射式光路对比,该方案更具有实用性,满足实际对准的要求。According to the technology characteristics of proximity and contact lithography,a practical reflective lithography alignment scheme is proposed.The differential Moiré fringe alignment technology is adopted in the scheme and alignment signal is carried in phase of Moiré fringe.Two sets of grating marks with placed oppositely direction and similar periods are designed on the mask and wafer,respectively.Charge coupled device imaging system is used to receive Moiré fringe image.Then,the relative position relationship can be obtained using Fourier transform to extract Moiré fringe phase.The designed marks could also detect position offset on the vertical and horizontal directions.The reasonable designed scheme of optical path is schematically given,the internal mechanism of the whole system alignment is analyzed in details,and the feasible mathematical model is established.This research results show that the maximum error is less than 0.002 pixel when alignment offset is less than 1 pixel.Compared with light path of transmission-type,the scheme is more practical,satisfying the requirements of the practical alignment.

关 键 词：光栅 光刻对准 反射式光路 叠栅条纹 光栅标记 

分 类 号：O436.1[机械工程—光学工程]