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

为了满足大容量存储和高速运行的要求，半导体是高度集成化的。曝光波长越短越好，以提高光刻的高空间分辨率，因为光刻的空间分辨率取决于波长。目前，ArF激光器正计划用于下一代光刻，其线宽分辨率有望达到90纳米。此外，下一代光刻技术打算使用157nm的F2（氟）激光器。除了氟化钙（CaF2）外，几乎没有选择光学元件的余地。但它具有双折射色散，如真双反射。这意味着双折射对短波长的响应增加。有必要改变以往利用可见光特别是氦氖激光进行测量的方法。因此，我们必须检查相同波长的光学元件。我们提出了一个Mueller矩阵偏振计和干涉仪，用于157nm代替双折射测量。此外，我们还设计了一种利用荧光玻璃的真空紫外线图像检测系统。研制了一种真空穆勒矩阵偏振计，用于在157nm波长测量部分氟化钙材料样品的穆勒矩阵。从测量的无样品米勒矩阵中，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。样品的双折射由米勒矩阵决定。实验结果表明，该Mueller矩阵偏光计可用于157nm光刻加工透镜材料的本征双折射特性的表征。

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.