SPTS uEtch

 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 (200°C-250°C for 2 min).


1. Maximum allowed booking per person between 9am and 5pm is 2 hours. It is still possible to get 4 consecutive hours from 7am to 11am or from 3pm to 7pm.
2. Reservation names must correspond to operators.


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

I. Introduction

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

Process name Pressure (Torr) Minimum etch rate (nm/min)*
Recipe1 125 12
Recipe2 125 38
Recipe3 125 125
Recipe4 125 153
Recipe5 125 175

*Values are for thermal oxide. Low temperature LPCVD, PECVD, ALD, evaporated and sputtered oxides will etch faster.

Etch rate depends on overall exposed SiO2 in the chamber (macro-loading). Values shown here are MINIMUM etch rates obtained at maximum loading by exposing a fully oxidised 4inch substrate (blanket thermal SiO2).

III. Operating instructions

  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 (200°C-250°C for 2 min).
  4. Pull on the PVDF arm, load the wafer and close the door.

5. Control the needle valve position

Needle valve position Pressure (Torr)
28.0 75
18.0 100
12.0 125
8.5 150

6. 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”.

7. Press “Start” to run the process while pressing “Press Here”

8. Check “Time Left”,

9. At the end of the process, press the button “Vent”

10. Open the door and unload the wafer

11. To put back the tool in Idle mode:

  1. Press “purge”  and wait the end (~4 min)
  2. Once the status is “Wait to vent” and the button “Vent”  is blinking, perform equipment logout on zone 02 computer.

12. Fill the logbook.

IV. Photos Gallery