Gentlemen, there are two factors possibly at work here.  One is that the
vacuum passageway is blocked, the other is that it is leaking.

Gary Hillman
S-Cubed
PO Box 365
9 Mars Ct.
Montville, NJ 07039
phone 973-263-0640 ex 35
fax 973-263-8888


-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of
Brad Cantos
Sent: Thursday, December 09, 2010 2:30 PM
To: General MEMS discussion
Subject: Re: [mems-talk] spin coater vacuum path


Jia,

I'm not familiar with this particular Laurel unit, but most spinners have a
vacuum interlock switch that prevents spinning if there is insufficient
vacuum at the chuck.  This can often get stuck if photoresist gets down the
shaft.  If your switch is making partial contact, it could explain some of
the symptoms that you are seeing.  I would look for this interlock switch
and clean it just as you did the solenoid.

Brad Cantos
[email protected]
http://holage.com