AG4108 Users meeting summary
Nabeel Robert Ibrahim
ibrahim at Stanford.EDU
Fri Jan 26 10:35:59 PST 2001
These are the major points that were discussed at the AG4108 User's Meeting
1) Having the 2nd AG RTA up and running would solve most of our problems
because we could use it as a metal contaminated system, however it will take
several months to set it up. Dick Crane should be notified of the
importance of the machine so that a timetable can be created for setting it
2) Because the chamber in the 4108 system has cold walls, the emission
of materials that had been deposited on the system walls was not
determined to be of great concern. Concerns about cross contamination
between silicided wafers and diffusion clean wafers were limited to the
- Does the presence of Cl and S (from our cleaning process)
result in volatile products (such as TiCl4)?
- Does material from the backside of a wafer get deposited on the
support pins and, if so, can it be transferred to subsequent wafers?
3) I will do some experiments to determine whether any cross
contamination can be detected by electrical measurements. I will
coordinate with Len to ensure that we have a clean chamber and will run
wafers for oxidation, then for silicidation, then for oxidation again.
The oxidized wafers will be used to build capacitor structures and I
will have the pre and post silicidation capacitor structures tested for
CV shifts and current through the oxide.
4) After running the experiments, I will write up a procedure for testing
the system for cross contamination. The cross contamination tests should be
run every 6 months.
5) If a user wants to put new materials into the system, s/he will be
responsible for running the cross contamination experiments.
6) We have several possibilities for processing procedures:
- STATUS QUO: Maintain separate quartz chambers and trays for clean
and silicide processing. Change them as necessary.
- SAME CHAMBER, DIFFERENT TRAY: Use the same chamber for clean and
silicide processing, but change the tray which holds the wafer. This
eliminates the possibility of cross contamination via the tray pins.
Mike P. and Len said that changing the tray should take about 15 minutes
and therefore is not a great burden on lab staff or users.
- SAME CHAMBER, SAME TRAY: Use all of the same quartzware for clean
and silicide processing. Cross contamination possibilities need to
be examined more before the procedure can be fully evaluated.
Tentatively, we will use the SAME CHAMBER, DIFFERENT TRAY procedure
until all testing is done. This allows for flexibility of the machine,
minimizes the chance of damaged quartware and eliminates most cross
If there are any questions or corrections, please email me.
More information about the AG4108