Magnetron Sputtering (CELLO Sputter System – Ohmiker 30CSL)
(1) Turn on the powers
Ensure power isolator, chiller, and power to the air
compressor and gas (N2, Ar) are turned on.
The N2 is used to vent the chamber and the Ar is used for generating plasma for sputtering.
This is a water chiller which cools down the heat of the target via water circulation.
(2) Turn on the sputtering machines
Switch on the main system by
(i) turning the key to “on”
(ii) press the Start button
(iii) press the pc power button
(iV) Run the “cello” software and login in
(3) Open the load-lock chamber
1. Press the “Manual” button to start auto-pumping to pump down the main chamber.
2. After the main chamber pressure reached below 1 x 10E-3 Torr, press the N2 valve to vent the loadlock chamber (to 7.4E-2 Torr) and load the sample substrate.
(4) Load the sample substrate
After putting the sample in the loadlock, go to Manual->Robot Control tab and press “Load Wafer” button to load the sample into the main chamber.
(5) Run the recipe program
1. Press load recipe from the process screen to select the recipe to use.
2. Press the Run button to start the process.
(6) Monitor the running progress
The Ar plasma will be turned on; the Ar ions are drawn to collide and etch the target. The target materials (e.g., ions/atoms/cluster) will drop off and deposit on the rotating sample substrate.
(7) Take out sample substrate
1. After the process has been completed, the wafer will be unloaded into the load lock. Press the N2 valve to vent the load lock and remove the sample.
2. After removing the sample, press “Loadlock Vacuum” to pump down the load lock.
(8) Shutdown the sputtering system
1. Press the MV valve to close the Main Valve
2. Press the Turbo pump shutdown button and wait for it to complete. N2 gas is introduced very slowly to reduce the speed of the pump.
3. Logout from the software and shutdown the PC.
4. Turn the key to off position
5. Turn off the chiller
6. Turn off the gas (N2 and Ar)
7. Turn off the air compressor
8. Turn off the power isolator
Bonus: Typical sputtering parameters are given for reference. Each sputtering system (even the brand of the target) has its own parameters; nonetheless, the data is a good point of reference to start from (Credit given to Dr. Cavin Ng, Dr. Dai Haiwen, Dr. Wang Hongyu, and Dr. Tang Zhe). Generally, the power is controlled between 50 W to 200 W at a fixed pressure of Ar (or N2 and O2), and the time can be controlled to obtain the desired thickness of materials. For a thickness < 100 nm, AFM shall be used for characterization; for a thickness > 100 nm, a thickness profiler can be used for characterization. Sputtered materials are generally nanocrystalline in nature. To promote crystallinity, a heating process can be performed in a tube furnace.
