---------------------------------- Forwarded ----------------------------------
From: Carol Adkins at MAPSNET-PO1
Date: 1/2/96 9:13AM
To: Floyd L Gentry at Mail-Sandia
*To: Edwin P Lopez at PO897CC1
*To: Jim Aubert at PO897CC1
*To: Edward M Russick
*To: [log in to unmask] at ccsmtp
Receipt Requested
Subject: RE:Supercritical CO2 Cleaning
---------------------------- Forwarded with Changes ---------------------------
From: Edwin P Lopez at PO897CC1
Date: 12/22/95 9:59AM
To: Carol Adkins at MAPSNET-PO1
Subject: Supercritical CO2 Cleaning
---------------------------------- Forwarded ----------------------------------
From: Floyd L Gentry at Mail-Sandia
Date: 12/13/95 4:15PM
To: edwin p LOPEZ at PO897CC1
Receipt Requested
Subject: Supercritical CO2 Cleaning
---------------------------- Forwarded with Changes ---------------------------
From: [log in to unmask] at hubsmtp
Date: 12/13/95 10:32AM
*To: [log in to unmask] at hubsmtp
Subject: Supercritical CO2 Cleaning
-------------------------------------------------------------------------------

     RE: Supercritical CO2 Cleaning, Jim Wrezel at Motorola Inc.
     
     We would be happy to test some of your boards in our supercritical CO2 
systems, although you would have to cut them up for preliminary tests.  We 
cannot handle the 18" X 24" board in any of our systems.  The 6" x 6" board 
would possibly fit in our 6" ID, 1500 psi system.  Our 5000 psi system has an ID
of 3".

     What are you looking to do with the technology?  We did some testing 
several years ago on PC boards and determined that the technology was not 
suitable for DOEs needs in flux removal.  We found that most electronic 
components are compatible with the CO2 and pressure.  However, hermetically 
sealed components with a sealed open volume (metal cover seal - hybrid 
microcircuits) suffered severe damage upon pressurization.  Since DOE has a lot 
of this sort of component, we abandoned the technology for that purpose.  The 
Kester 197 RMA flux we tested was not soluble in SCCO2.  Occasionally it would 
pop off due to infiltration of the high pressure CO2 into microcracks that would
expand upon depressurization.  However, if a solvent and SCCO2 are combined into
a hybrid cleaning system, the volume of solvent is greatly reduced and a dry 
board results upon removal from the system.  Again, the effect of pressure on 
the sealed components forced us to stop research on the technology for cleaning 
PWBs.

     If you would like to talk further, please give me a call.

                                                Carol Adkins    
                                                Sandia National Labs
                                                (505) 845-9119
                                                [log in to unmask]


______________________________ Forward Header __________________________________
Subject: Supercritical CO2 Cleaning
Author:  Edwin P Lopez at PO897CC1
Date:    12/22/95 9:59 AM


     Ed:
     
     This is a request that I got through the IPC TechNet.  Do you have any 
     ideas?  If you do, let me know, or send a response directly back to 
     [log in to unmask]
     
     Thanks
     Floyd Gentry
     
     
______________________________ Forward Header __________________________________
Subject: Supercritical CO2 Cleaning
Author:  [log in to unmask] at hubsmtp
Date:    12/13/95 10:32 AM
     
     
Does anyone know of a source where we could clean some populated printed 
wiring boards using supercritical carbon dioxide (CO2)?  We are interested in 
evaluating component compatiblity as well as board/solder resist 
compatiblity.  Cleanliness analysis and reliability tests will also be 
performed.
     
The boards range in size from 6" X 6" to 18" X 24".
     
Thank you for your assistance,
Jim Wrezel
Motorola Inc.
(708) 632-6513