Technics PE II-A
The Technics PEII-A is a plasma etching system used for descumming/ashing of photoresist and nitride etching. The chamber accommodates multiple 4 wafers or a single 6 wafer. This system may be used either in manual or auto mode.
Available Gases:
- O2 (Gas 1)
- CHF3 (Gas 2)
- SF6 (can be connected instead of CHF3 on Gas 2)
Process Recipes
Note: We do not have flow control for any gases, only pressure.
Descum
This is used after developing exposed photoresist, before hard baking, to eliminate any residual scum, which may be present. Settings:
- Gas: O2 (Gas 1)
- Flow: 51.1 sccm
- Power: 50 Watts
- Pressure: 270-280 mTorr
- Time: 1 min.
Resist Stripping or Ashing
For complete removal of standard hard baked G and I-line photoresist. Settings:
- Gas: O2 (Gas 1)
- Flow: 51.1 sccm
- Power: 300 Watts
- Pressure: 270 - 280 mTorr
- Time: 7 min.
Use this procedure to clean the chamber before doing any SF6 nitride etching. Settings:
- Gas: O2 (Gas 1)
- Flow: 51.1 sccm
- Power: 300 Watts
- Pressure: 300 mTorr
- Time: 20- 30 min.
Precautions and Hints
- Always leave the vent on when you begin a pump down -- switch vent off after 2-3 seconds. This will sweep the oil that has collected at the hose end near the chamber back toward the mechanical pump. (Note: The SOL'N should always be OFF when you vent the chamber, but VENT should always be on when you begin to pump down the chamber.)
- Always leave the vent on when the chamber is open.
Starting Up
- The vacuum pump should be off. It will need to be plugged in to start. The plug (large round shape) is located near the outlet behind the PEII-A.
- Check the status of the controls on the front of the machine. It should be in the following condition:
| Parameter | Setting |
| Main Power | ON |
| Mode | Manual |
| Solenoid | Closed |
| Vent | Closed |
| RF Power Switch | OFF |
| RF Power | Fully counterclockwise (0) |
| Gas 1 | OFF |
| Gas 2 | OFF |
- When you are ready to introduce your sample, vent the chamber by toggling the VENT switch. Be sure that the solenoid (SOLN) on the vacuum line is closed when you do this. It will take about 15 seconds for the chamber to fill.
- Once it is at atmospheric pressure, open it carefully (the top is very heavy) and place your wafers on the plate. Close the top carefully, being sure not to allow it to fall.
Running the System
Manual Mode
- You are now ready to start the vacuum pump. Leaving the VENT ON, toggle the SOLN (vacuum pump) switch open. After 2 or 3 seconds, close the VENT switch to allow the pump to lower the pressure of the chamber.
- When the system reaches 30 mtorr, you can introduce the gas you wish to use into the chamber by toggling the appropriate gas switch. Use the knob to set the desired gas pressure in the system.
- Turn on the RF power and turn the dial clockwise until the desired power is reached. You can see the plasma through the window on the front of the chamber.
- Begin timing your run.
- When the run is complete, turn off the RF power first. ALWAYS turn off the RF power before turning off the gas.
- Close off the GAS switch and allow the chamber to pump down to 30 mtorr so you can be sure all gases have been swept out of the chamber.
- Turn off the vacuum pump by switching the SOLN toggle to the closed position. Now you may vent the chamber by switching the VENT toggle on.
- The chamber pressure will now come up to atmosphere and you may remove your sample.
Auto Mode
- To run the system in auto mode, it is a good idea to preset the power and gas flow settings by running the desired gas into the chamber and striking a plasma following the above procedure. Set the pressure and then the power and then return the system to standby.
- Once the power and pressure are set, and your wafers have been loaded into the chamber, switch Mode to AUTO. Auto mode overrides any manual control over the system, so you may proceed to:
- Open the solenoid (SOLN).
- Close the VENT.
- Turn on the RF Power switch. Do not touch the knob as you have preset the power.
- Turn on the required gas.
- Set the time.
- Note that in turning on all these switches nothing happens... yet. Now you are ready to begin your run.
- Push the white START/STOP button on the front of the system. The chamber will pump down, start gas flow, strike a plasma and time your run. When time is up, the system alarm will sound. Push the START/STOP button to silence the alarm. The system should now be pumped down. This is done by returning the system to manual as follows:
- First, close off the power, and the gas toggles. Leave the SOLN open, so that when you return the mode to manual, the pump will start and the system will pump down. When the system reaches base pressure, shut off the vacuum pump and vent the chamber to remove your sample.
- Remember always to close the solenoid once the system is down to base pressure to prevent back streaming of pump oil. Then disable the system.
Restoring the System to Standby
- Once your sample has been removed, close the chamber and start the vacuum with the vent open. After a couple of seconds, close the vent and allow the chamber to pump down to 35 mtorr. Close the SOLN. Be sure that gas switches and RF power are off. Leave the main POWER on. Unplug the vacuum pump (large round plug). [http://microlab.berkeley.edu/labmanual/chap7/7.11.html|UC Berkeley Microlab Manual link]