纳米光刻对准方法及其原理

Overview of Alignment of Nanometer Lithography Techniques

对准技术对光刻分辨力的提高有着重要作用。45nm节点以下的光刻技术如纳米压印等,对相应的对准技术提出了更高的要求。对光刻技术发展以来主要用于接近接触式和纳米压印光刻的对准技术做总结分类,为高精度的纳米级光刻对准技术提供理论研究基础和方向。经过分析,从原理上将对准技术分为几何成像对准、波带片对准、干涉光强度对准、外差干涉对准及莫尔条纹等五种对准方法。最后结论得出基于条纹空间相位的对准方法具有最好的抗干扰能力且理论上能达到最高的对准精度,而其他基于光强的对准方法的精度更易受到工艺涂层的影响。因此,基于干涉条纹空间相位对准的方法在纳米级光刻对准中具有很好的理论前景。

The alignment technique plays an important role in high resolution of lithography. A lithography below 45 nm node such as nanoimprint lithography will place much more importance upon alignment technique. The alignment techniques about proximity and nanoimprint lithography ever since the development of lithography technique are summarized to provide the base and direction for theoretical research of alignment technique. Through analysis, alignment techniques are theoretically classified into five sorts： geometrical imaging way, zone-plate alignment, intensity-information-based way, optical heterodyne way and fringes-phase-based Moiré way. The results show that the fringes-phase-based way can achieve the best anti-jamming ability and the highest theoretical resolution whereas other ways suffer from process-induced variations more easily. Therefore, the fringes-phased- based way has more theoretical prospect in alignment of nanometer lithography.