Development of molding process to reproduce micro-structures of 100 nm pitch at a wide area of 100 mm - side square

本研究的目的是发展一种新的成型工艺，以在100mm见方的大面积上复制100nm间距的微结构，用于一种新的光学元件。为了实现这一目的，本研究执行了三个项目：（a）局部控制成型过程，（B）在模具表面精确制造微结构，和（c）光学元件原型。（a）在注塑或热压等成型过程中，控制模具表面的表面温度和热流以及型腔中的再生材料的压力。结果表明，当模具与复制材料第一次接触后仅一秒内表面温度应保持在玻璃化转变温度（Tg）或更高时，可以复制微观结构，而复制材料的压力可能很低，甚至在几MPa。（B）使用电子束光刻和快速原子束（FA B）蚀刻在用于玻璃热压的陶瓷模具的SiC材料上制造微结构，并将聚焦离子束（FI B）在用于塑料注射成型或热压的金属模具的Ni镀材料上弯曲。而闲置的方形凹槽在FAB刻蚀后在陶瓷模具上被制成梯形凹槽，或者在FIB弯曲后在金属模具上被制成圆形底部凹槽。（c）光学元件，如线和空间光栅的原型：在凹槽上有金属线的偏振板，或者只有特殊光是透明的滤色器，因为每个间距都是为特殊光设计的。它们可以实现使用麦克斯韦方程模拟的光学性能。

The purpose of this research is to develop a new molding process to reproduce micro-structures of 100nm pitch on a wide area of 100mm-side square for a new optical element. To realize the purpose, the research executed the three projects : (a)locally controlling the molding process, (b)precisely fabricating the micro-structures on the mold surface, and (c)prototyping the optical element. (a)The surface temperature and heat flux on the mold surface and the pressure of the reproduced material in a cavity ware controlled in the molding process like injection molding or hot pressing. In result, we revealed that the micro-structures could be reproduced when the surface temperature should be hold at the glass transformed temperature (Tg)and more during only one second just after the first contact between the mold and the reproduced material, while the pressure of the reproduced material might be low even at several MPa. (b)The micro-structures were fabricated using electron beam lithography and fast atom beam (FAB)etching on the SiC material of a ceramics mold for glass hot pressing, and focus ion beam (FIB)curving on the Ni plated material of a metal mold for plastic injection molding or hot pressing. The idle square groove, however, was made as a trapezoid groove on the ceramics mold after FAB etching, or a round bottom groove on the metal mold after FIB curving. (c)The optical elements like a line ＆ space grating were prototyped : a polarized plate with metal lines on the groove, or a color filter where only special lights are transparent because the each pitch is designed for the special light. They could realize the optical performance as simulated using the Maxwell equation.