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Center of MicroNanoTechnology CMi

SPTS uEtch

SPTS uEtch

Attention To be read first:
  • Ask staff for materials compatibilities before processing!
  • Some materials are known to be not compatible with the tool:
    • Polymers (PR, Quickstick, Tape, ...)
    • Soda-lime (float glass), Borofloat
    • Ge
    • Ti, TiN
    • Ta, TaN, TaOxide
    • Silicon Nitride (Subject to exceptions)
  • Before processing, it is highly recommend to bake the sample (200C-250C for 2 min).

Contents: CMI

  1. Introduction
  2. Processes available
  3. Operating instructions
  4. Photos gallery

I. Introduction CMI

The SPTS uEtch performs a vapor phase; selective, isotropic etch on sacrificial oxide to release a device.

The VHF process uses reduced pressure, gas phase, anhydrous HF and Alcohol to etch sacrificial SiO2 for MEMS release in a non-polluting, vacuum-based system. This produces a clean, residue-free release etch that does not require liquids or supercritical drying. Because no liquids are used in contact with the MEMS devices, by-products are removed in the gas phase, and contamination and stiction-creating conditions are avoided.

II. Processes available CMI

Process name Pressure (Torr) Etch rate (nm/min)
Recipe 1 125 11.6 - 13.3
Recipe 2 125 37.5
Recipe 3 125 125
Recipe 4 125 153
Recipe 5 125 175

III. Operating instructions CMI


  1. System is in Idle mode by default: no wafer is loaded and the chamber is under vacuum.
  2. Press "Vent"
  3. Reminder: Before processing, it is highly recommend to bake the sample (200C-250C for 2 min).
  4. Pull on the PVDF arm, load the wafer and close the door.



  5. Edit the recipe:
    1. Select the recipe.
    2. Change the duration of the "ETCH" step in sec. The minimal duration recommended is 15 mins to guarantee an optimal etching cycle.
    3. Choose how many "CYCLES" (= number of repetitions of the the "ETCH" step).
    4. Save modifications.
    5. Leave the Edition mode by pressing "process".


  6. Press "Start" to run the process while pressing "Press • Here"
  7. Check "Time Left",
  8. At the end of the process, the chamber returns automatically at atmospheric pressure
  9. Open the door and unload the wafer
  10. To put back the tool in Idle mode:
    1. Press "purge"
    2. Wait for Pressure ≤ 0 Torr
    3. Press "stop"
  11. Fill the logbook.
  12. IV. Photos gallery CMI


    Figure 1: Suspended Polysilicon Membrane (Recipe 5 60 min) - Adrien Toros EPFL | Q-LAB.


    Figure 2: Suspended Polysilicon Membrane (Recipe 5 60 min) - Adrien Toros EPFL | Q-LAB.


    Figure 3: Suspended Polysilicon Membrane (Recipe 5 60 min) - Adrien Toros EPFL | Q-LAB.


    Figure 4: Suspended Polysilicon Membrane (Recipe 5 60 min) - Adrien Toros EPFL | Q-LAB.