A New Projection Exposure Method Using a Liquid Crystal Display as a Switching Matrix in Place of a Reticle
A new concept of a projection exposure system is proposed. In the new system, a liquid crystal display (LCD) is used in place of a conventional reticle, and arbitrary patterns are introduced on the LCD by a computer keyboard. After investigating what types of LCDs are suitable, and what exposure con...
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Published in | Japanese Journal of Applied Physics Vol. 39; no. 1R; p. 324 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
01.01.2000
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Online Access | Get full text |
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Summary: | A new concept of a projection exposure system is proposed. In
the new system, a liquid crystal display (LCD) is used in place of a
conventional reticle, and arbitrary patterns are introduced on the LCD
by a computer keyboard. After investigating what types of LCDs are
suitable, and what exposure contrast is obtained, a prototype test
exposure bench is manufactured using a LCD panel that is detached from
a notebook computer. The bench has a camera lens with F-numbers of
2.8–16 as a projection lens. The LCD dots are of size 263×263 µm
2
, and each dot includes red, green and blue filter
cells. Patterns on the LCD are replicated onto the wafer on a scale of
1/14.3. It is clarified that a maximum contrast of 4.9 is obtained
when blue and black designations are used as transparent and opaque
cells respectively. Since color LCDs are composed by such red, green
and blue cells, the transparent part cannot be stitched in the lateral
direction. However, in the longitudinal direction, patterns are
stitched quite smoothly, and quasi-arbitrary patterns are replicated
successfully. |
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ISSN: | 0021-4922 1347-4065 |
DOI: | 10.1143/JJAP.39.324 |