X-ray or gamma ray systems or devices – Specific application – Lithography
Patent
1995-09-22
1997-03-18
Porta, David P.
X-ray or gamma ray systems or devices
Specific application
Lithography
378 35, 378 36, G21K 500
Patent
active
056129866
ABSTRACT:
Methods for forming X-ray images having 0.25 .mu.m minimum line widths on X-ray sensitive material are presented. A holgraphic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required.
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Howells Malcolm S.
Jacobsen Chris
Lawrence Berkeley Laboratory, University of CA
Porta David P.
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