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Add-on a real-time watchdog and monitoring with graphic
display
By adding an independent
real-time data collection, display and analysis system with sophisticated
alarms, errors are eliminated, historical analysis is enabled, and both
historical and real-time data can be displayed.
Can predict and alarm on beam current and energy errors, disk rotation
and scan,
Electron-shower, DCM, source, chamber and beamline pressure, source
filament current and voltage, AMU, wrong
process,
etc.
Data can be selected by lot numbers, recipes, locations,
full SPC on all parameters is available, remote access and tool-to-tool,
batch-to-batch comparison, etc.
Some typical screen
examples:
Process
and Machine Problems
Electron-shower
failure caused wafer charging. About 1000 wafers with zero yield were run
before the damage was detected at a routine test. It took another 24 hours
to understand the cause of the failure. (Wafer charge damage can only be
detected using an electrical test).
The
damage was calculated as follows:
| Cost
of scrapped wafers - 1000 wafers @ $300/wafer |
$300,000 |
| Machine
downtime to find the cause and fix - 24hours @ $500/hour |
$12,000 |
| Process
and maintenance work - 50 Hours @ $100/hour |
$5,000 |
| Cost
of test wafers - 30 wafers @ $20/wafer |
$600 |
| Delayed
product, re-catch production, est. - 1000 wafers @ $50/wafer |
$50,000 |
| Other
equipment idling, 1% low overall fab utilization - 24hours @ $600/hour |
$14,400 |
| Total
one-case loss |
$382,000 |
The
TadiGuard Solutions
After
the catastrophic occurrence, a TadiGuard was immediately installed. The
outputs of the DCM (Discharge Current Monitor) voltage, the Electron-shower
currents and voltages were connected to the TadiGuard and alarm levels
were set. In addition, the end-station is fully monitored, the acceleration
and extraction voltage and current are monitored, the AMU number, vacuum
levels, sliding seals and many other parameters are now in full control.
Ultimate
Results
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A
crash situation like the one mentioned above can not happen again, since
the machine will be stopped if a critical parameter deviates from pre-set
boundaries.
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Wafers
that were previously in doubt (end-station 'freeze', with risk of double
implant or no-implant) are now easily moved-on with no risk.
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"Crashes"
are now minimized.
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Less
engineering work, tests, test wafers and maintenance adjustments are needed.
Over-All
Fab Yield, Capacity And Profitability Were Increased!
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