RIE 1C Operation Procedure

 

Tool Power-up:

 

  1. Turn on the N2: above the tool on the wall there will two valves. Open the valve to the left a few turns, but don’t adjust the regulator to the right.  The regulator pressure should read about 14 psi.
  2. Turn on the cooling water: the blue water circulator to the left of the tool should be turned on using the switch on the front of the tool.
  3. Open the process gas valves: open the oxygen tank by unscrewing the valve on top of the tank.  Do not adjust the valves on the oxygen regulator.  Next open the valve on top of the etchant gas, C3F8 octofluoropropane.  DO NOT adjust the regulator valves.
  4. Turn on the Main Power to the RIE-1C: Open the darkened translucent panel on the front of the tool and press the green “On” button.  This will supply power to the tool and also turn on the power to the vacuum pump and the RF generator.  ***If nothing comes one then check the breaker switch on the back of the tool.
  5. Check RF power generator: The front panel of the generator will light up when it is supplied with power.  If it is not lit then turn on the power by using the power switch on the back of the RF generator, which is located inside the base/cabinet.  If it does not light then contact the tool supervisor.
  6. At this point the water pump should be running, the vacuum pump should be running, the nitrogen ballast valve gauge on the vacuum pump should indicate that nitrogen in flowing, and the RF power generator and the etching chamber segment should indicate that they are supplied with power.

 

Running a process:

  1. Determine the basic process parameters: Gas flow values or the corresponding pressure values, along with the amount of power to be used should be determined before starting up the process. 
  2. Opening the process chamber: once the tool is powered up, press the “start” button and then the “reset” button on the front of the tool.  “Start” initiates the etch process by pumping down the chamber, and “reset” interrupts the process and vents the etch chamber.  After the chamber has fully vented an alarm will sound which may be silenced by pressing the “reset” button.
  3. Load the substrate into the etch chamber: making sure that it is in good contact with the underlying surface and is within the circular area defined for substrate positioning.
  4. Close the chamber lid: after inspecting the o-ring for particles. Any particles should be removed by gently wiping the o-ring with a lint free wipe.  Add a sparing amount of vacuum grease if necessary.
  5. Set the process time: open the cover on the front of the etcher and adjust the timer.  Adjust both the value and the unit to reflect the proper amount of time.  For example: 2 min could be entered as 2 x m, 20 x 0.1m or 120 x s.
  6. Activate the gas valve buttons: GV1 and GV2 should be turned on (the green LED will light) in order to use the corresponding gases.  If only one gas is desired then the other valve may be left in the off (unlit) position.  GV1 controls C3F8 while GV2 controls O2.
  7. Set RF power: Use the RF power controller dial on the front left of the etching unit to select a setting which has historically supplied the desired power level.  Consult the process log for historical data.  For example: a setting of 546 on the RF power “odometer-style” dial will result in a power of approximately 110W.  The resulting power level will not be visible until RF power is turned on after gas flow stabilization.
  8. Press start:  the valve between the vacuum pump and the chamber will open and the chamber will be pumped down to 10 mTorr.  Watch the pressure and be ready when the chamber reaches this base pressure.
  9. Adjust gas flow:  when the chamber pressure reaches 10 mTorr the gas flow will start but the RF power will not be turned on.  Over the next thirty seconds gas flow should be adjusted with the two gas flow needle valves on the front left of the etcher.  Using the needle valve adjust the flow to the particular sccm rate or the pre-RF pressure desired(note: pressure will increase 5-10% with applied RF power).
  10. Adjust RF power: after the gas flow stabilization period the RF power will come on.  Use the RF power dial to adjust the forward (FWD) power level to the desired intensity.  Next use the phase and then the load dials to adjust the reflected (REF) power keeping it as close to 0 or 1 W as is possible.  Extremely short etches may require a dry process run in order to set the RF power, lest it be too unstable and disrupt the etch.
  11. Observe the plasma: Using the window near the top of the front panel the purple glow of the plasma should be observable.  If the plasma continuously flickers or appears unstable hit the reset button to abort the process.  Instability may be the result of arcing, which can result in damage to the tool or poor etch quality.
  12. Monitor the process: Particularly if the process is long remember to periodically monitor the etch for gas flow stability and RF stability.  The process timer will indicate the percentage of the time remaining. 
  13. System Vent: When the time has expired the RF power will be turned off, the gas valves, GV1 and GV2, will be close, and the chamber will be pumped back to the base pressure value of 10 mTorr.  The chamber will then be vented to atmosphere with N2.  When the venting is completed an alarm will sound.  This can be silenced by hitting the “reset” button.
  14. Remove your substrate: after silencing the alarm open the chamber lid and carefully remove your substrate being careful to minimize scratches.
  15. Further Etching:  if you wish to etch further under the same conditions then place your next substrate into the chamber and hit start,  otherwise return to #1 under “running a process”.

 

Powering down the system:

  1. Unless you are going to be using the system again in the next few minutes it is best to power off the tool after pumping the chamber back down.  The chamber should be held at vacuum when not in use.  This prevents the adsorption of gas and water molecules, which are best left out and can otherwise slow the pump down process.
  2. Turn off the GV1 and GV2 buttons so that the associated LEDs are not lit.
  3. Turn off the RF power:  using the toggle switch on the back of the RF power unit(not the etcher itself).
  4. Close the lid and press the start button: the system will pump down to the base pressure of 10 mTorr.
  5. Press the red Off button: on the front of the tool when the pressure has reached 10mTorr.  The power will go off but the chamber vacuum will be maintained.  Don’t wait longer for further pump down as the tool will then enter into the normal process cycle.  No gases will flow as long as GV1 and GV2 are closed, but if the process is short it may vent  the system once the timer has expired.
  6. If you will be etching shortly then you may choose to leave the main O2 and C3F8 cylinder valves open, the nitrogren line valve open, and the water circulator on.  If you have no plans to use the tool in the next half hour then close or turn off these components.