한국광학회지 (Korean Journal of Optics and Photonics)
- 제4권4호
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- Pages.373-380
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- 1993
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- 1225-6285(pISSN)
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- 2287-321X(eISSN)
모든 3차 수차와 5차 구면수차를 제거하여 얻은 극자외선 리소그라피용 5-반사광학계
Five Mirror System Derived From the Numerical Solutions of all Zero 3rd Order Aberrations and Zero 5th Order Spherical Aberration for DUV Optical Lithography
초록
축소배율(M=+1/5)을 갖는 극자외선(deep ultra-violet) 리소그라피용 5-반사광학계를 설계하였다. 먼저 모든 3차 수차와 5차 구면수차를 영으로 하는 수치적인 해를 구면에 대해서 구하였다. 다음 비교적 크게 나타나는 잔류 수차(구면수차, 코마)의 제거를 위하여 마지막 두 반사경에 대하여 비구면화를 optimization방법에 의해 이행하였다. 이렇게 하여 얻은 광학계는 광원을 KrF 엑시머 레이저(파장
A five mirror system with a reduction magnification(M=+1/5) is designed for DUV optical lithography. Initially, numerical solutions of all zero 3rd order aberrations and zero 5th order spherical aberration are obtained for the spherical mirror system. Next, by the optimization method, the aspherization is carried out to the two spherical mirrors to obtain a system that has as less residual aberrations, higher NA and improved MTF as possible. We have finally obtained the system of which NA is 0.45 and the resolution is about 500 cycles/mm at the 50% MTF value criterion and the depth of focus of
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