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Venting/Pumping Growth Module for Cell Maintenance

Venting/Pumping Growth Module for Cell Maintenance

Paraphrased from a Veeco technician's procedure as well as the Gen10 manual itself

Venting

First, verify there is no platen on the growth stage and the gate valve between the cluster and GM is closed

  • Cool cells to room temperature and set the substrate temp to 200C (can be up to 400C to expidite the LN2 boil off process)

  • Close off LN2 and wait for it to be boiled off (day before)

  • Power off the substrate heater

  • Power off all sources, RGA, BFM, rheed, ion gauges

  • Heated viewport power should be set to 0

  • Shut off cooling water and purge all water lines connected to the growth chamber. Dump excess water into drain/bucket using spare hose connected to drain nipple.

  • Close cryo gate valve

  • Turn off ion pump controller

  • Attach UHP nitrogen to the venting/pumping port on the chamber and turn up to 15psi (right now the line is Tee’d from the Bravo growth chamber line, it needs its own wall regulator if possible)

    • A note on the above, the manual states to set a regulator to 3psi of N2 and to wait approximately 20 minutes for vent to finish. There is no pirani gauge within the growth module, so there it no way to know exact pressure. This is why a burp valve was included that lets the user know when they are at atmospheric pressure.

  • Open all metal valve on the pump/vent port and allow nitrogen to flow until the overpressure valve starts burping, this means you are at atmosphere.

 

Pumping

Pumping down a GM from atmospheric pressure to UHV, this will require some help from the LL roughing pump and turbo pump

  • Initially the ion pump will be off and the cryo gate valve will be closed

  • Make sure that the LL turbo pump and scroll are off and the LL is at atmosphere

    • Install a rough pump line between the venting/pumping port on the LL turbo-pump isolation space (?)

    • Connect the other end to the growth module venting/pumping port

  • Open the all metal valves for those two ports so both chambers are at the same pressure

  • Begin the LL pump down procedure, in the Lot manager software start the pump sequence on the load lock

  • When the pirani gauge reads below 1e-3 Torr, turn on the ion gauge filament in the growth module, once it reads below 1e-5 Torr we can close the all metal valves for the LL and GM ports

  • Then we can immediately power on the GM ion pump and open the cryo gate valve and wait for pressure to get below 5e-7 Torr. At this point we can start running an RGA scan.