激光光刻是加工微光学及二元光学掩模的主要手段。光刻的最细线宽对所加工的二元微器件性能起决定作用。本文导出了会聚的高斯光束用于激光光刻时在光刻胶内的光场近似分布形式,由此可判断出能光刻线条的分辨力。若入射高斯光束受到振幅或相位调制时,胶层内的光强分布将发生变化,从而影响曝光线条的线宽和质量。计算看出:当入射光中心环受到遮拦时,可以得到超过光刻物镜极限分辨的线条宽度(0.6μm),但此时对曝光能量控制要求很高。在激光直接写入系统上的曝光试验结果与理论计算相符。

Laser lithography is one of the main methods for manufacturing micro-optical and the binary optical masks. The smallest linewidth produced by laser lithography plays an important role in the properties of the micro-optical elements. The collimated laser beam (He-Cd laser λ=442 nm) was focused on the photoresist for exposure and light intensity distribution in the photoresist was derived out on the approximate assumption. One of its main properties, namely lithography resolution, was analyzed based on the light intensity distribution in the photoresist. When the incident beam is modulated by the amplitude elements or the phase elements, the light intensity distribution in the photoresist will be changed, and therefore the quality of the exposure line will be affected. The results of the calculations showed: normally, 1.0 μm linewidth on photresist can be achieved, when the central circle of the incident beam is obstructed, a super resolution linewidth of 0.6 μm can be achieved for the lithography lens, microscope objects (NA=0.65, 40x). However, it requires a more rigorous exposure energy control. The experimental exposure results on the laser direct writing system showed good agreements with the theoretical calculation.