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Polarized illumination system give 20% resolution gain |
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Feb 04, 2005 at 06:00 PM |
 Product Briefing Outline: Nikon Corporation has
developed "POLANO," (Polarization Optimization for Lithographic Advance
in NSR Optics) a polarized illumination system that improves image
contrast by 20 percent in order to realize a half-generation advance in
resolution. Beginning in the Spring of 2005, plans are to offer POLANO
as an option on the NSR-S308F, Nikon's latest model ArF excimer
stepper, which will start shipping in December of 2004.
Problem: As progress continues on increasing the speed and density
of VLSI chips, there has also been a demand for ever-higher N.A. values
for the projection lens installed in steppers. Ordinary illumination
light is composed of light that is randomly polarized in several
directions. It includes s-polarized light, which increases image
contrast, and p-polarized light, which degrades image contrast. As the
N.A. of the lens increases, the adverse effect p-polarized light has on
contrast tends to grow. If, in order to achieve a high-contrast image,
only s-polarized light is used for exposure then exposure power
declines and throughput suffers.
Solution: With the development of the POLANO polarized
illumination function, Nikon has succeeded in changing illumination
light into s-polarized light that boosts image contrast without losing
exposure power. This technology improves image contrast by 20 percent
in order to achieve a half-generation advance in resolution.
Demonstration experiments were completed in October 2004 using an
NSR-S307E ArF excimer stepper (N.A. 0.85), and techniques for measuring
the degree of polarization have been developed. After further
refinements, POLANO is scheduled to be available as an option on the
NSR-S308F ArF excimer stepper (N.A. 0.92).
Applications: Available as an option on the NSRS308F ArF excimer
stepper (N.A. 0.92). Nikon Step-and- Repeat Systems. POLANO can also be
installed on ArF immersion steppers to even further improve the
resolution and image contrast of those models.
Platform: POLANO will also be available for installation on the
Nikon ArF immersion stepper, which will have an N.A. exceeding 1.0, and
is slated to start shipping in the latter half of 2005.
Availability: March 2005 onwards.
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Product Briefings 
