张绍锋 1曹艳翠 1张璇 1李丹 2胡潇 3刘巨澜 3姜秀丽1
作者信息
- 1. 中材人工晶体研究院有限公司,北京 100018
- 2. 北京中材人工晶体研究院有限公司,北京 100018
- 3. 中材人工晶体研究院有限公司,北京 100018||北京中材人工晶体研究院有限公司,北京 100018
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摘要
Abstract
Illumination system,as one of the main parts of lithography,enables to supply high uniformity intensity distribution on the mask,controls exposure dose and creates off-axis illumination(OAI)modes,which enhance the resolution and enlarge depth of focus of lithography.Quartz crystals exhibit intrinsic birefringence in the x-direction,based on which,quartz crystal polarization device is made,and the polarization state of beam can be controlled by the device.In the lithography machine's lighting system,the resolution ratio and imaging quality can be further improved by the polarization device with off-axis illumination modes assisted.Due to the limitations of traditional quartz crystal growth process and crystal automorphism,large-diameter quartz wave plate(diameter above 50 mm)which the polarization device need was always a challenge.In this study,optimized framework seed method was applied to eliminate heritable etch channel defects.Raw material ratio was optimized for further reduce the content of trace elements such as Al3+ and Na+,etc.Temperature-rising curve was controlled to realize lattice matching on the surface of quartz seed,and weaken inhomogeneous in the epitaxial region of quartz crystal.The parameters(such as temperature,pressure,mineralizer and its concentration,opening rate of throttle flap,et al.)were systematically adjusted for quartz growth.Thereby a high transmittance quartz single crystal suitable for 193 nm wavelength was successfully synthesized and a quartz wave plate blank with maximum size ofϕ160 mm was processed,which is the largest size quartz optical wave plate blank reported.Optical properties such as trace element content,internal transmittance,birefringence performance,optical uniformity and laser damage resistance were characterized.The results show that,the total content of trace elements in quartz crystal is controlled within 7×10-6,the internal transmittance reaches 99.80%/mm,the unevenness of birefringence difference is less than 0.029 7%,and the PV value of optical uniformity reaches 3.9×10-6(effective aperture ϕ140 mm).关键词
石英晶体/照明系统/深紫外/波片/偏振装置/水热法Key words
quartz crystal/illumination system/deep ultraviolet/waveplate/polarization device/hydrothermal method分类
数理科学
