Problem evalign SNF 2009-03-17 14:26:02: left side mask moves and loss of focus

mahnaz at mahnaz at
Tue Mar 17 14:26:02 PDT 2009

After aligning the mask and focusing it when loaded the wafers the target on the left side moved and lost focus.
I unloaded and loaded the mask 3 times and it happened every time.
It seems to be an issue with the Z hight and the system makes jerky movement and some times loud noises.
I am not sure precision alignment is possible under this condition at all.
Secondly, about a year ago we lost the capability of centering the chuck, we are still in the same position and very hard to center the chuck, it needs to be resolved or we need to come up with something new. Those # from while back is not even close to have the chuck centered.

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