Muk,

I don't know of any such studies off the top of my head.  It seems that
the percent open area combined with dose is causing the pellicle to
burst as you have noted.  I have run reticles with a wide variety of
%open and %closed and high doses but always bladed off to small areas.
Perhaps you can get a thicker pellicle from your vendor to withstand
higher internal cavity pressure?



Best Regards,
Garrett Oakes


-----Original Message-----
From: Muk Mei Yu [mailto:ahyao_mymuk@yahoo.com]
Sent: Monday, July 28, 2008 8:22 AM
To: mems-talk@memsnet.org
Cc: muk mei yu
Subject: Re: [mems-talk] Pellicle life

Hi Garrett Oakes,

I'm using 7.25" pellicle on PE maskplate for 6" wafer.
The exposure energy varies from 190, 220 to 380MJ with the % clear area
(non-chrome area of the plate) of ~60, ~70 & ~2% respectively.
Data collected show that pellicle with 220mJ/70% active clear process
tends to break more frequently than the other two.
Normally my pellicles will break by itself in burst-out manner halfway
during exposure or even sitting in the storage rack.
I suspect temperature and humidity (and it's fluctuation) are the main
contributors to pellicle breakage,
but there is no opportunity for me to study. Is there any study done to
check the correlation between temperature/humidity and pellicle
breakage?

Thanks,
Muk