![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/03/CPD_Z14.jpg)
Important to know:
- Ethanol is to be asked by email/phone to CMi staff (Patrick Madliger) at least half a day before using CPD.
I. Supercritical point dryer
This installation is dedicated for drying freshly released structures with minimum sticking issues (samples are dried at CO2 supercritical point).
![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/03/diagrammePT.gif)
At the very beginning, samples are kept into ultra pure ethanol at room temperature. Temperature is then dropped down to 6°C before ethanol is substituted by CO2 is in its liquid phase.
During the HEAT mode, the pressure and the temperature are increased (A -> B -> C) in order to reach the critical phase.
During the BLEED and VENT mode the pressure and the temperature are decreased to reach the gaseous phase (C – > D -> E) without directly crossing the transition liquid to gaz that is responsible for stiction of critical suspended structures.
II. Modus operandi
- Log ON the tool on Zone14 computer and check in grey room at back of the tool that the CO2 bottle is open.
- Turn the chiller ON for at least 30 minutes prior to process run.
- Turn the condenser on.
- Turn the chamber on.
The chamber should be at atmospheric pressure. If not, the system will tell you. Use the VENT valve on screen if needed.
When a pressure of “0 psi” is confirmed, open the lid and carefully place it on a soft surface (clean room tissue) face down
![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/11/CPD_Z14_1.jpg)
- Enter “User/Sample Information”, if required. If not, press directly “Main Menu” and “Auto” mode.
![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/11/CPD_Z14_2.jpg)
- Factory Default values may be used or updated from the Auto Mode Setup screen.
- Press NEXT to advance screen and to start “Auto Mode”.
![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/11/CPD_Z14_3.jpg)
- Introduce ultra-pure alcohol into the chamber. Fill the chamber with sufficient alcohol to cover the samples. NEVER EXPOSE CHAMBER TO ANY ACIDS.
- Carefully transfer the samples into the system process chamber. For best results, minimize exposure time to air.
- Carefully lower the chamber lid onto chamber. Initially use fingers to evenly tighten the 8 knurled nuts around the circumference of the chamber lid. Use the spanning wrench provided to uniformly tighten each knurl nut in a “star pattern”. Tighten the knurl nuts in the numbered sequence. Repeat this rotation “star pattern” sequence until the knurl nuts are unable to tighten further.
![](https://www.epfl.ch/research/facilities/cmi/wp-content/uploads/2020/03/chamber_closure_sequence_1.jpg)
- Once lid is secure, press COOL button, and follow instructions on screen!