Institute of Nanophotonics Technology, School of Physical Science and Technology, Sichuan University, Chengdu 610064, China.
Opt Lett. 2012 Jan 15;37(2):247-9. doi: 10.1364/OL.37.000247.
We propose a new direct writing nanolithography approach using a plasmonic focusing device and a nano silver mirror with dual-wavelength illumination for high exposure depth. Arrays of pyramid aperture are used to focus the incident light beams into 80 nm light spots. The pyramid combined with a thin silver film coated on the substrate constructs a surface plasmon polaritons (SPP) coupling cavity, which amplifies the intensity of the light field in it by SPP effect and resonance. The transmission depth of the standing wave formed by forward and reflected light could reach hundreds of nanometers. Two lasers with different wavelengths are used as illumination sources to homogenize the light field through complementation between the two standing waves. Simulation results show by using 355 nm and 441 nm wavelengths, a space of 44 nm at the bottom of the photoresist could be obtained after exposure and development. The feature size of resist patterns could be further scaled down, depending on the optimization of parameters of photoresist exposure and development, illumination wavelengths, etc.
我们提出了一种新的直写纳米光刻方法，使用等离子体聚焦装置和具有双波长照明的纳米银镜实现高曝光深度。金字塔形孔阵列用于将入射光束聚焦成 80nm 的光斑。金字塔与涂覆在基底上的薄银膜结合构成表面等离子体激元（SPP）耦合腔，通过 SPP 效应和共振增强腔内光场的强度。由前向光和反射光形成的驻波的透射深度可达数百纳米。两个不同波长的激光器用作照明源，通过两束驻波的互补来实现光场的均匀化。模拟结果表明，使用 355nm 和 441nm 波长，在曝光和显影后可以在光刻胶底部获得 44nm 的空间。根据光刻胶曝光和显影、照明波长等参数的优化，还可以进一步缩小抗蚀剂图案的特征尺寸。
