From mahnaz at stanford.edu  Mon Mar 30 16:14:00 2009
From: mahnaz at stanford.edu (Mahnaz Mansourpour)
Date: Mon, 30 Mar 2009 16:14:00 -0700
Subject: overlay is off
Message-ID: <49D15238.5050202@stanford.edu>

Hello all,

I ran a second layer on the tool and:

If you use the align check button,  the system will show you how much 
drifts after it goes to contact. Although i separated the wafers and 
mask and readjusted it and it was perfect alignment after development
*Left side of the wafer was off more than 10 to 20 um in Y and 10 um in 
X and right side did slightly better, this is with flat of the wafers 
toward you. *
I did not see this drift in Contact/align/expo button.
I strongly suggest do not use the system for second or consequent 
layers, meaning that the system is not able to do overlay at the moment.
Move you work to Karlsuss.
I am not shutting down the system because still can be used for *ONE 
LAYER ONLY.*

mahnaz