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.
- 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.
- 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.
- “Crashes” are now minimized.
- Less engineering work, tests, test wafers and maintenance adjustments are needed.
Over-All Fab Yield, Capacity And Profitability Were Increased!