Next quake could shutter Taiwan
fabs for a year, SEMI reports
By Anthony Cataldo
EE Times
(12/02/99, 2:47 p.m. EDT)
HSINCHU, Taiwan — Taiwan's semiconductor industry was only a
few kilometers shy of being dealt a punishing blow that could have
shut its fabs for months after a 7.6-magnitude earthquake struck
the island last September, knocking out power and leading to almost
half a billion dollars in lost production. But the fabs were lucky to
come out relatively unscathed, as the concentration of fabs near
Hsinchu was far enough away from the earthquake for which they
were otherwise ill-prepared, according to a report presented this
week at SEMI Japan. The fabs still risk serious structural damage in
the likely event that a quake hits closer to Hsinchu, the report said.
The biggest problems cited by a group of consultants that worked
with SEMI (Semiconductor Equipment and Materials International) to
investigate the effect of the earthquake on Taiwan's semiconductor
industry were fab equipment that was improperly anchored down,
poor piping and duct installation, risk of fire and a lack of emergency
preparedness.
What's more, the building codes currently being followed by industry
may not be stringent enough to prevent serious damage in the
event of another quake, according to consultants who presented
their findings.
The quake occurred roughly in the middle of Taiwan about 68 miles
south of Hsinchu Science-Based Industrial Park, the site of 28
fabrication facilities, where about 10 percent of the world's chips
and 80 percent of its PC motherboards are manufactured. After
personally visiting six fabs and gathering information from 14 more,
the consultants said they were surprised to see such little damage
considering the oversights.
The "vast majority" of production line equipment was not adequately
bolted in, said Brian Sherin, managing principal with Environmental
and Occupational Risk Management (Sunnyvale, Calif.). Some of the
equipment was bolted down but only at a few points, rather than at
every corner. And in some cases where the equipment was secured,
it was anchored to a tile floor designed to be removed to allow
access to plumbing, rather than to steel or a concrete slab below.
Other times, the bolts were too small for the sockets. And some
equipment had no anchoring at all.
"There were many cases when equipment vendors did a good job
installing anchors but they were never bolted in," Sherin said.
Fortunately for Taiwan's fabs and their customers in the electronics
industry, the fabs did not get hit with enough seismic "acceleration"
to overcome the friction between the floor and the equipment. The
consultants estimate it would take a jolt equivalent to at least 20
percent of gravity to knock down a piece of equipment; in the
September quake, the fabs experienced an acceleration of 10
percent to 15 percent of gravity, they said.
"The biggest impact was a business interruption due to the loss of
electricity," Sherin said. "But if [the earthquake] had been farther
north you would have seen acceleration exceed 20 to 25 percent of
gravity, and we would have seen a lot more equipment topple."
Though equipment didn't overturn, not all fab tools came away
clean. Vibration-sensitive equipment like vertical diffusion furnaces,
which are as high as four meters and contain tall and fragile quartz
reaction tubes, failed, as did lithography equipment. The
combination of the tool failures and 10 days of power outages
caused $440 million losses in semiconductor production, but the
asset loss was only about 5 percent of that, according to the
report.
Along with equipment installation, piping and ductwork were also
found to be in poor shape at the older fabs. In some cases ducts
were attached to single hangers, which made them susceptible to
excessive swaying. And pipes were commonly hung from other pipes
— a practice that should be avoided, according to the report. Five
sizable pipe leakages were reported as a result of the quake. In one
case, a cleanroom was flooded in almost 8 inches of water, which
destroyed one stepper.
Poor installation of piping can exacerbate the risk of fire if a sprinkler
system is not installed properly, which can make sprinkler heads
susceptible to damage. In one incident following the quake a fire
started when a generator overheated and caught fire 40 hours after
the quake, destroying the generator and damaging transformers.
The fire overpowered the CO2 sprinkler system and had to be
contained by handheld fire extinguishers because the area fire
department couldn't respond quick enough. "If it had been a much
larger incident, we would expect to have seen more fires," Sherin
said.
The investigation team found that the fabs involving hazardous
materials fared much better during the quake. Newer facilities have
been designed with seismic sensors that shut down equipment at or
below 5 percent of gravity, which is more sensitive than the 15
percent of gravity considered standard in the United States. Bulk
gas containers and liquid systems were found to be well anchored,
though there were reports of some minor plumbing leaks.
There was little structural damage to the buildings themselves aside
from some minor cracking and loss of tiles on exterior walls, though
the seismic joints adjoining one office tower and fab was reported to
have significant damage.
One potential problem is that fabs in Taiwan use a kind of steel
frame that was found to be susceptible to cracking after an
earthquake in Northridge, Calif. in 1994, which prompted a change in
U.S. building codes. "The frames would be susceptible to significant
damage if an earthquake occurred in the Hsinchu area," said John
Dal Pino, principal of Degenkolb Engineers (San Francisco).
And there's evidence that such a quake could happen. Taiwan,
which straddles two colliding tectonic plates, is riddled with fault
lines up and down its western region, Dal Pino said. There's one
running close to the fab park that caused an earthquake with a
magnitude of 7 to 7.5 in 1935. If a quake that big were to hit the
area before more precautions are taken, "instead of a shutdown of
two weeks you're looking at six to 12 months or longer," Sherin said.
The investigation team will present its findings next week in Taiwan
at the Industrial Technology Research Institute gathering, and later
to the Silicon Valley Manufacturing Group. The team will encourage
chip manufacturers to do more to incorporate earthquake
preparedness into the corporate culture. It will also recommend that
chip makers follow a set of seismic guidelines that will be issued by
SEMI. This will include working with tool vendors to design and install
equipment able to withstand shaking at 63 percent of gravity for
production equipment, and at 93 percent for hazardous production
materials.
"It's been a wake-up call," Sherin said. "They need to do a much
better job of installing tools with seismic protection in mind."
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