For the benefit of those interested in IPA drying, I might be able to assist
in understanding what types are available.
IPA drying has been around for many years. The orginal designs used a
chamber or sump of boiling IPA to create a vapor zone that the wafers would
be lowered into. The IPA vapor displaces the water on the surface even in
trenches or topography. Afterward the wafers are raised into an area with
cooling coils and allowed to cool until they are dry. Several companies made
these and they are probably still available. The IsoDry (model name) was a
product of this type made by Verteq, who acquired the product from a startup
called Applied Cleaning Technologies or ACT.
The early technology used large amounts of IPA which was costly and required
special abatement equipment. Current IPA drying is based on the Marangoni
principal. These dryers have a rinse tank where a small amount of IPA is
added to the surface of the water. The tank is then drained slowly and the
IPA displaces the water as the tank drains. This is usually followed by a
final dry using high volumes of N2.
CFM, who was purchased by Mattson, patented a dryer using the marangoni
technique and they have sued several other companies for infringement.
Mattson also purchased Steag who was one of the companies that had been
succesfully sued by CFM. Mattson still uses the CFM marangoni dry as part of
their wet process stations, but I don't think they sell it as a stand-alone
dryer.
The product sold by AIO was called the Sonic Fog, it was similar to the CFM
dryer but generated IPA vapor using an ultrasonic to atomize the liquid.
This product has since been refined and is now sold by a company called
L-Tech. http://ltechcorp.com It's called the Avid Dryer.
Yield-up was another company which made a Marangoni type dryer that survived
a CFM suit. This company was bought by FSI International and I believe they
are selling these as stand alone tools.
There is also a single wafer IPA drying technology called Rotagoni, which
was developed by IMEC. It uses a spin chuck with a means for depositing the
IPA similar to how it's done in a Photoresist track. IMEC licenses
technology and I don't know if there is anyone offering this as a tool yet,
but there probably will be at some point.
That just about covers all the bases. Hope you found it interesting.
m
-----Original Message-----
From: mems-talk-admin@memsnet.org [mailto:mems-talk-admin@memsnet.org]On
Behalf Of Bill Moffat
Sent: Monday, March 11, 2002 8:51 AM
To: mems-talk@memsnet.org
Subject: RE: [mems-talk] Wafer Drying
Roger,
I saw a copy of that IsoDryer at a trade show about 5 years ago. It
was
being displayed by Dale Ann Springer who worked for A.I.O. at the time. I
have a buddy who works for A.I.O. at this time, Suzanne Scullen. I will try
to reach Suzanne to see what she knows about this type of dryer and try to
find Dale Ann to see what she knows. When I have collected data I will be
back at you. I may have to call you to relay all of the details. Bill
Moffat.
-----Original Message-----
From: Roger Brennan [mailto:rogerbr@earthlink.net]
Sent: Monday, March 11, 2002 6:21 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Wafer Drying
Hi Everybody:
I have an "Iso-dryer" (a vapor "de-greaser" using isopropyl alcohol) ready
to be replaced. It has been suggested that I replace it with a Marangoni
drier. As I understand this system, a layer "atomized" mist of very small
liquid droplets of isopropyl hovers over the top of DI wafer. As the
wafers move from the DI water to the iso, the wafers are supposed to be
dried. So far, I have talked to the vendor, Avid Technology, Mountain
View, CA, www.Itechcorp.com
Sounds like magic! Is anyone out there using such a system and are you
happy with it?
Thanks,
Roger Brennan
Home:
1403 Forrestal Avenue
San Jose, CA 95110
(408)453-0711 (telephone)
(408)573-9407 (fax)
rogerbr@earthlink.net
Work:
Endevco
355 N. Pastoria Ave.
Sunnyvale, CA 94085
408-739-3533 ext 204
roger.brennan@endevco.com
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