Development of evaluation system of optical elements for vacuum-ultra violet

为了满足更高容量存储和高速操作的要求，半导体被高度集成。由于光刻的空间分辨率取决于波长，因此曝光波长变得越来越短以提高光刻的高空间分辨率。目前ArF激光器正计划用于下一代光刻技术，其线宽分辨率有望达到90 nm。此外，下一代光刻技术打算使用157 nm的F2（氟）激光。除了氟化钙（CaF 2）之外，几乎没有光学组件的选择余地。然而，它有双折射色散，如真正的双折射。这意味着双折射随着短波长的增加而增加。因此，有必要改变用可见光特别是He-Ne激光进行测量的旧方法。因此，我们必须在相同的波长下检查光学元件。提出了一种用于157 nm波长的Mueller矩阵偏振计和干涉仪，以代替双折射测量。此外，我们还设计了一种新型的真空紫外荧光玻璃图像检测系统。研制了一种真空缪勒矩阵旋光仪，用于在157 nm波长下测量样品的缪勒矩阵，部分样品为氟化钙材料。从无样品测量的Mueller矩阵中，我们发现了探测器的吸收误差和四分之一波片的取向误差对测量结果的影响。样品的双折射率由Mueller矩阵确定。实验结果表明，该矩阵偏振计可用于表征157 nm光刻透镜加工材料的本征双折射。

Semiconductors are highly integrated for the requirement of higher mass storage and high speed operation. The wavelength for exposure becomes shorter and shorter to improve high space resolution of lithography, because the space resolution of lithography depends on the wavelength. Now ArF laser is planning to be used for next generation of lithography and its resolution of line width is expected 90 nm. Moreover, the next next generation of lithography is intended to use a F2 (fluorine) laser in 157nm. There is little room for option of optical components except a calcium fluoride (CaF2). However it has birefringence dispersion such as true bireflingence. It means that birefringence increases in response to short wavelength. It is necessary to change the old way to measure by using visible light especially, He-Ne laser. Therefore we have to inspect optical components in the same wavelength. We propose a Mueller matrix polarimeter and interferometer for 1 57nm instead of birefringence measurement. Moreover, we purpose a novel image detection system for vacuum ultra-violet using a fluorescent glass. A vacuum Mueller matrix polarimeter is developed for measurement of the Muller matrix of samples, partially, calcium fluoride materials in 157nm wavelength. From the measured Mueller matrix with no sample present, we found the influence of absorption error in the detector and orientation error in quarter-wave plates on measurement results. The birefringence of samples is determind from the Mueller matrix. Experimental results show this Mueller matrix polarimeter is available to be used for characterizing the intrinsic birefringence of materials for processed lens at the 157nm lithography.