개선된 투과형 타원계를 사용한 러빙된 Polyimide 배향막의 초미세 위상지연 정밀 측정
Precise Measurement of Ultra Small Retardation of Rubbed Polyimide Alignment Layer Using an Improved Transmission Ellipsometer
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초록
시료를 회전시키는 기존의 시료회전형 타원계에서 시료를 고정시키고 편광자모듈을 회전시키는 모듈회전형 타원계로 구조를변경하고 광원교체와 회전모듈 동기화, 배경 미세이방성 보정 등을 통해서 위상지연값 측정정밀도를 <0.005 nm 까지 향상시켰다. 개선된 모듈회전형 타원계를 사용하고 RVD(Retardation Vector Difference) 방법을 도입함으로써 1.0 nm 정도의 잔류이방성을 가지는 유리기층의 효과를 배제한 러빙된 Polyimide 배향막의 순수 배향효과만에 의한 초미세 광학이방성을 정밀하게 측정하는 방법을 제시하였다. 순수 러빙으로 인한 배향막의 위상지연값은 0.05 nm 에서 0.15 nm 정도의 크기를 가짐을 확인하였다.
Abstract
The precision of retardation measurement has been improved upto <0.005 nm after improvements are made to theconventional transmission ellipsometer. Improvements are made such that, i) the polarizer module instead of the sample stage isrotated, ii) the light source is replaced, iii) the starting points of two rotating modules are accurately synchronized, and iv) thefine background retardation is compensated. Together with the newly introduced RVD (Retardation Vector Difference) method,the improved instrument is successfully applied to characterize the ultra small optical birefringence of the rubbed polyimidealignment layer, after the residual retardation due to glass substrate whose magnitude is about 1.0 nm is properly subtracted. Itis verified that the net retardation of the alignment layer ranges from 0.05 nm to 0.15 nm.
참고문헌 (15)
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