[labnetwork] Critical Point Dryer Problem

[Michael Whitley]

We've been having an on-going problem with our Tousimis Autosamdri
815B, Series B critical point dryer. We are able to successfully run
1cm die though the system, but 100mm wafers come with parts stuck,
contaminated and sometimes there are still liquid drops left on top of
the water. We have shipped the system back to Tousimis and it checked
out OK at their facility.

We have replaced the following filters and parts:

-  Internal Pre- Fill 0.5um Particulate Filter
-  Internal Post-Fill 0.5um Particulate Filter
-  0.5um Purge Line Filter Element
-  LCO2 Oil/Water Filter Element on LCO2 Filter Assembly, Gasket & O-Ring
-  0.5um Particulate Filter in T-Filter Element on LCO2 Filter Assembly
-  High Pressure 10ft hose changed out with 5ft hose for Chamber LCO2
Supply Only (New Cylinder)
-  Chamber O-Ring
-  Wafer basket and rings

And we have used the following solvents in the chamber:

-  2-Propanol Optima LC/MS, 99.9% - Fisher Scientific (Note:  packaged
under Nitrogen, 0.2 micron filtered)
-  Ethanol - ≥99.5%, anhydrous (200 proof) - Sigma Aldrich
*Note: Both of the alcohols above have been further filtered manually
with a 0.2um filter prior to processing.

After all of this we are still getting wet wafers and stuck parts. I
was hoping someone might have a suggestion on something else to try.

Best Regards,

Michael

-- 
Michael R. Whitley, PE
Vice President of Engineering | EngeniusMicro, LLC
107 Jefferson Street N, Huntsville, AL 35801
256-261-1260x124 | michael.whitley at engeniusmicro.com