Direct-write X-ray lithography using a hard X-ray Fresnel zone plate.
Results are reported of direct-write X-ray lithography using a hard X-ray beam focused by a Fresnel zone plate with an outermost zone width of 40 nm. An X-ray beam at 7.5 keV focused to a nano-spot was employed to write arbitrary patterns on a photoresist thin film with a resolution better than 25 nm. The resulting pattern dimension depended significantly on the kind of underlying substrate, which was attributed to the lateral spread of electrons generated during X-ray irradiation. The proximity effect originated from the diffuse scattering near the focus and electron blur was also observed, which led to an increase in pattern dimension. Since focusing hard X-rays to below a 10 nm spot is currently available, the direct-write hard X-ray lithography developed in this work has the potential to be a promising future lithographic method.
Department of Physics and Photon Science and School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, South Korea.
Su Yong
SY
Lee
Department of Physics and Photon Science and School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, South Korea.
Do Young
do Y
Noh
Pohang Accelerator Laboratory, POSTECH, 80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk 790-834, South Korea.
Hae Cheol
HC
Lee
Pohang Accelerator Laboratory, POSTECH, 80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk 790-834, South Korea.
Chung-Jong
CJ
Yu
Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
Yeukuang
Y
Hwu
Department of Materials Science and Engineering, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 501-759, South Korea.
Hyon Chol
HC
Kang
Fresnel zone plate; X-ray writer; backscattered electrons; direct-write X-ray lithography; proximity effect