Interesting article and breakthrough:
07:45 PM ET 02/25/98
Major chip advance by Univ. of Texas with DuPont
By Therese Poletti
SAN FRANCISCO (Reuters) - A University of Texas graduate
student team and DuPont Photomasks Inc. have achieved a major
breakthrough in semiconductor production design that was not
believed possible with current technology.
A team of graduate students led by Grant Willson, professor
of chemistry and chemical engineering, has produced a
semiconductor wafer print etched with the finest transistor line
width yet, a feat not expected by the industry until at least
2007-2008 with futuristic techniques now in research.
The University of Texas in Austin created a silicon wafer
''print'' with features measuring at 0.08 micron, a way to
measure the fine line-width of elements that make up transistors
on a semiconductor. One micron is approximately 1/25,000th of an
inch; current semiconductors are using .35 or .25 micron
technology.
But industry executives said the key to the research
breakthrough is that the team created the wafer print -- which
has no working transistors -- on a slice of silicon using
current optical technology instead of using one of many
futuristic techniques now being researched that use new light
sources such as extreme ultraviolet lithograhy, X-ray
lithography and others.
''I didn't believe it could be done at first,'' Willson said
in a statement. ''It really works better than my wildest
imaginings ...'' He said there appeared to be room to generate
even smaller features.
The project was funded by Sematech, an industry reserach
consortium of 10 semiconductor companies.
The Austin, Texas-based team created these ultra-fine
features using a photomask produced by DuPont Photomasks Inc. at
their Round Rock, Texas, facility; a photoresist process
developed by the University of Texas team; and a piece of
chip-making equipment known as a stepper made by a little-known
company called ISI.
''It's going to take five to six years to know if this is
commercially viable,'' said Ken Rygler, executive vice president
of worldwide marketing at DuPont Photomasks. ''There are many
hills to climb, but it's an important proof of concept.''
Rygler said it was a plus and surprising that all the
technology used in the process is available now.
Round Rock-based DuPont Photomasks -- which was spun off
from chemical giant Dupont Co. a year and a half ago -- is the
world's leading maker of photomasks, the translucent plates
containing precision images of a chip's features. Those features
are transferred to a silicon wafer by exposing the wafer to
ultraviolet light beamed through the mask.
The wafer is covered with an oxide insulation layer and then
coated with film. When the light beamed through the photomask
hits the film, the film hardens. The wafer is then subjected to
an acid that etches the insulation below, exposing the silicon.
These and other steps are repeated again and again, creating
the transistors.
As chips become more powerful, more transistors are placed
on a single chip. Intel Corp.'s Pentium II microprocessor, for
example, contains 7.5 million transistors.
To make chips with even more transistors, the light source
has to become thinner and thinner, in order to create finer
lines in the masking process. The light now used is invisible to
the human eye.
''We are already in the invisible-light wavelengths,'' Intel
spokesman Howard High said, referring to the industry's current
use of ultraviolet light sources that measure 193 nanometers to
develop chips that are about .25 micron.
The development by the University of Texas researchers was
especially impressive, executives said, because it was achieved
with light measured at 193 nanometers, instead of a light stream
measured at an even thinner 13 nanometers, used in extreme
ultraviolet research.
''It tells us that optics have a lot more life in them than
people thought,'' said Dan Hutcheson, president of market
research firm VLSLI Research Inc., adding the development was
''pretty phenomenal.''
''It's pretty hard to paint a two-inch line if its a
four-inch paint brush,'' Hutcheson said.
But the industry is not likely to cut back any of its
research into the post-optic technologies, where many companies
are spending millions of dollars in research groups such as a
consortium Intel has founded with chip-making rivals Motorola
Inc. and Advanced Micro Devices Inc. . International Business
Machines Corp. and Lucent Technologies Inc. also each have big
research into X-ray lithography.
''I suspect that work will continue,'' DuPont's Rygler said.
''... That's why a $2,000 PC gets more powerful every year.''
^REUTERS@ |
