Optical: systems and elements – Absorption filter – Neutral or graded density
Patent
1998-06-30
2000-02-01
Spyrou, Cassandra
Optical: systems and elements
Absorption filter
Neutral or graded density
355 67, 355 71, G02B 522
Patent
active
060210095
ABSTRACT:
A technique for improving across field dimensional control in a microlithography tool. In a lithography imaging process in which a pattern on a mask is projected to form latent images in a photosensitive medium, the critical dimension distribution across the imaging field varies due to scattering and other factors. An optical compensator having gradient neutral density filter properties is used to reduce the intensity of light at those locations corresponding to regions of an imaging field having higher exposure dose. By reducing the intensity of light at the higher dose regions, the overall dose profile is made more uniform, which reduces linewidth variations when devices are fabricated on an semiconductor wafer.
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Borodovsky Yan
Troccolo Patrick M.
Intel Corporation
Schuberg Darren E.
Spyrou Cassandra
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