Field service update ....
shott at stanford.edu
Tue Jun 1 17:19:09 PDT 2010
Frank Monano from STS Field Service arrived mid afternoon. He had time
to adjust the rotational alignment of the carousel so that wafers are
now well aligned on the chuck as determined both by the mark on the
backside of the wafer from the lip seal as well as based on the shadow
of the clamp fingers on the top side. That alignment looks good and
well matched in both carousel position #1 and in position #2.
During the course of the afternoon, we loaded approximately 6 wafers
from each of the two carousel positions and did not see the situation
that others have reported where a wafer does not actually end up on the
chuck but comes back out on the carousel. Others have reported that
this happens when the wafer is mounted in carousel slot #1 but not when
in slot #2 (the number is stamped in the carousel at the 9 o-clock
position of the wafer nearest you when the load door is up and you are
standing at the end of the machine).
We have cleared the wafer loading shutdown so that some may be able to
get some useful etching overnight. To be conservative, I suggest that
you load your wafers in carousel slot #2.
Note: Frank believes that we may still have to adjust the reed switch
that determines when the pins are fully lifted during the wafer
loading. If that switch engages too soon while the pins are still
lifting, the carousel arm will begin to retract before the wafer is
fully lifted. This will result in the failure to load a wafer and it
will still be sitting on the carousel arm ... although offset towards
In any event, we are hopeful that some of you may be able to get some
useful etching done this evening.
Tomorrow morning we hope to look at the "clearable" RF error and look in
detail at the positioning of the lift pins relative to the switch that
senses the wafer up position.
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