Preparation & PPE
Preparation - Planning is key to a successful PM. Be sure to book the tool in LMACS at least 1 week prior to the planned work. Login to the tool using the nanoFAB.Equipment Service when starting the work.
PPE -Full face mask, hair net, gloves, lab coat
- Box Wrenches
- Allen Wrenches
- IPA & cleanroom wipes
- Ultra-Solv pads
- Vacuum Compatible Aluminum Foil
- Vacuum Grease
- Replacement O-Rings (insert size / qty)
- House Vacuum
- Sandblaster (to clean parts)
- Vent chamber
- describe procedure (can follow the procedure as described in SOP)
- Turn off ION gauge
- Close cryo pump isolation valve and capman isolation valve
- Vent the chamber with N2
- Turn off cryo compressor
- Purge cryo pump for a minimum of 4 hours with N2. (recommended by manufacturer of cryo pump) The cryo turns into a block of ice and the 4 hour purge is used to dry it out and purge trapped gases from the charcoal array.
- If the chamber needs cleaning continue.
- Remove tin foil from inside chamber
- Remove chimney and sandblast
- Clean inside of chamber with Ultra-Solv pads
- Replace acetate film over view port if needed.
- Remove cooling block from hearth and clean.
- Clean hearth
- Vacuum the inside of the chamber
- Wipe the inside of the chamber and hearth with IPA.
- Remove the chamber door o-ring and hearth access o-ring clean both it with IPA. Grease with a lite layer of vacuum grease
- Wipe the 2 surfaces of the chamber door and hearth access where it seals with IPA
- Replace the o-ring's
- Sandblast all of the parts removed, blow off with CDA and polish with wire wheel on grinder.
- Re-line the chamber with vacuum grade foil
- Wipe all of the parts removed with IPA and replace in chamber
- Close the chamber and pump down to cross over pressure. ~300 mTorr or lower
- Check the static charge in the cryo compressor and top up with Helium if needed.
- Clean the two cryo pump vent o-rings with IPA and grease with a lite layer of vacuum grease (I grease these o-rings to prevent leaks)
- After a minimum of a 4 hour purge with N2, rough out the cryo pump to bellow 50 mTorr, you may have to pump purge the cryo pump with N2 to achieve this.
- Turn on the cryo compressor and confirm that the temperature of the cryo pump is decreasing
- Once the cryo pump temperature is below 20 Kelvin the gate valve for the cryo pump can be opened if the chamber pressure is at crossover (the cryo pump will take over 3 hours to reach 10 Kelvin)
Document the work
Complete the form below to document your work. If there was any additional work done outside the scope of the procedure listed above, be sure to create a separate blog entry to capture the additional work. Ensure that you label the content appropriately.