
Canon was among the first to begin work on the development
of F2 (157nm) scanner technology. Its subsequent
collaborative work on a prototype platform and process
development has been underway since early 2000.
This program, involving joint work with several industry
partners, is on track to produce a F2 beta
system, the FPA-5800FS1, by the fourth quarter of 2003;
then a production system, the FPA-6000FS2, by early 2005.
By the time the FPA-6000FS2 is launched, its platform
will have been used in high volume manufacturing down
to the 65nm node with several generations of KrF and ArF
Canon scanners.
The extensive IP Canon gained through its early work
with x-ray imaging technology, has given it a significant
head start in F2 system development, particularly
in overcoming the two major problem areas— lens
coating and chamber purging.
The durability of coatings for lenses and mirrors in
a 157nm optical system has been dramatically enhanced
by Canon’s new high-density deposition process.
Evaluations of HR and AR coatings applied by this process
show virtually no degradation after 60 million 22mj/cm2
pulses.
Since oxygen strongly absorbs 157nm radiation, Canon
is designing several well-integrated systems into its
F2 tools to purge everything from the beam
path. These include--
--Separate N2 circulation systems for the reticle and
wafer stages.
--N2 purged load locks at areas of wafer and reticle transfer.
--Conditioning/filtering systems to purify the circulating
nitrogen and minimize its consumption.
--Thermal isolation and stability for the entire exposure
system, achieved by containing the main body and other
modules in a temperature-controlled chamber.
Recognizing the progress in the development of pellicle
materials and formats to meet the extreme demands for
157nm exposure, Canon has designed its FS1 projection
optics to be field adjustable-- to accommodate either
a traditional organic pellicle or a hard pellicle.
In designing the novel catadioptric lens system for its
F2 system, Canon has drawn from previous generations
of KrF and ArF lenses, and is making full use of its highly
advanced projection lens manufacturing and tuning process,
which it calls "wavefront engineering." As with
its previous generations of lithography tools, Canon has
developed and built it’s own at - wavelength PMI
system for 157nm lens tuning.
Because the success of F2 depends heavily
on the availability and quality of a special type of glass,
Canon, in August 2001, completed its Optron facility for
large-volume manufacturing of high-grade calcium fluoride
crystal for use in lenses for its ArF and F2
scanners.