SEMICON West '07: EUV Camps Grow Further Apart

There was lots to be said about extreme ultraviolet (EUV)
lithography at SEMICON West — some of it good, some of it not
so good. On the one hand, Cymer announced that it would be
ASML’s EUV source supplier going forward. Along with that
announcement, Cymer detailed the advances made in its
laser-produced plasma (LPP) source design (Cymer switched from DPP
to LPP three years ago). Cymer has managed to get IF power up to 50
W, which is significant progress in output power. And the
lithography source manufacturer promises to reach 100 W by the end
of the year (and, according to Cymer’s Nigel Farrar, the company
has hit every one of its marks since setting its roadmap at the
beginning of last year). That’s downright close to the target the
industry has been aiming for to achieve production throughput on
EUV litho tools. But it is, of course, a moving target. Setbacks in
resist dose and the number of mirrors needed in the EUV system
threaten to keep boosting the power needed from the source. The
power requirement could actually go up by a factor of two or three,
Farrar said.

There’s still a lot of murmuring from the rest of the industry
about debris mitigation with these EUV tools. But Cymer has made
significant progress there too, enabling a collector lifetime of
about a year. Nonetheless, Cymer has its work cut out for it now.
The next 18 months will show whether the engineers can really pull
it all off and meet the schedule ASML has in place.

Certainly, plenty of people in the industry are not convinced
that EUV lithography is the right way to go. They are latching on
to double patterning as a way to get them to 32 nm (since there’s
little doubt that EUV won’t be the answer at that node, anyway).
EUV has become an Intel-led political battle, with many employees
jumping ship because of it — whether immersing themselves in
Sematech activities or full-out quitting their current companies,
they are finding ways to get away from the EUV development
work.

Not surprisingly, the folks at nanoimprint lithography toolmaker
Molecular Imprints
do not speak highly of EUV. I met with them at SEMICON West, where
they detailed many of the difficulties EUV is facing. The meeting
was arranged by John Doering, who said he left ASML for Molecular
Imprints specifically because of ASML’s dogged focus on EUV
lithography, and the unwillingness to spend any time or money
exploring what he saw as the more sensible nanoimprint approach.
Mark Melliar-Smith, CEO of Molecular Imprints, wondered aloud why
chipmakers would want to use a technology that wasn’t likely to
take them very far. “I don’t think EUV can get down to 10 nm,” he
said.

Nanoimprint lithography has its own hurdles to overcome, of
course, but that’s a story for another day…