{{images:plasmalab.jpg?width=200}}

====== Description ======
The Oxford PlasmaLab 90+ is a parallel plate etcher in the RIE configuration with a
grounded upper electrode through which gas is injected and a RF driven lower electrode
of which the RF power or self-bias can be set. 6 gas channels are available, gases can be mixed
with MFC's, process pressure is regulated by feeding the value from the gas-independent baratron
(diaphragm gauge) to an MKS control valve that throttles the turbo pump. Substrate temperature can
be set from 0-60 C. 

The system has a loadlock and fully automated loading/unloading that allows use of toxic gases.

==== Current gas configuration ====  

  * SF6
  * CF4 
  * O2
  * Ar
  * CHF3
  * empty slot
====== Manual PlasmaLab 90+ ======
The technical logbook can be found [[PlasmaLab 90+ logbook|here]]

DO NOT USE THIS SYSTEM FOR Ar+ SPUTTER ETCHING! USE THE IBE ETCHER INSTEAD!!!

===== Before you start =====
  - You should have followed the intro for this apparatus and know the relevant safety measures (where to find emergency off switches, gas valves and fire alarms)
  - Create an entry in the logbook, leaving sufficient space to document the result later on
  - Log in
  - In case the system is inactive:
     - Start the chiller pump (611)
     - Switch on chiller cooler(!) (611) 
     - Set 6.0 bar compressed air (611)
     - Open BOTH (red) cooling water valves behind the system(!)
     - Verify that purge N2 regulator setpoint is 1.5 bar
     - Verify that vent N2 regulator setting is 0.6 bar
     - Switch on chamber rotary pump (software, load panel)
     - Switch on loadlock rotary pump (software, load panel)
     - Evacuate chamber
     - Close all gas cylinders (in 611 and 613)
     - Perform a leaktest, pumpdown on time, time=0
     - Repeat 3 times, now leak rate should be 0.0 mtorr/min, if not: stop & warn me!
     - Stop & exit leak test
     - If leaktight: open gas tanks. Check optimum setpoint of the pressure regulator as well (according to the Millipore / Tylan FC260 4V flow controller manual) is 30 psig, that's 2.0 bar absolute or 1.0 bar overpressure)
  - Chamber must be at base pressure (<1e-5 torr) before processing

//Note: currently (august 2010) the cooler is defect. Cooling is performed with tap water (tap is in room 611). Choose 92 'C as your process temperature (this will not be the real temperature!), otherwise the machine will get stuck in the "adjusting temperature" step at the start of a process.//

===== Loading your samples =====
DO NOT LEAVE THE LOADLOCK VENTED LONGER THAN 5 MINUTES

  - Vent the loadlock if necessary (see below)
  - WEAR GLOVES
  - Make sure the quartz wafer is centered on the transfer mechanism, place your substrates or wafers on top
  - Click button to evacuate loadlock, push down loadlock lid
  - Loadlock must be at 1e-4 torr (preferably 1e-5) before loading


===== Conditioning the reactor =====
  - Make sure chiller cooling is on and at desired temperature(!)
  - With the 'Select' button, run the appropriate conditioning recipe
  - Note actions in logbook

===== Process =====
  - On the 'Load' page, click 'Load' to load the wafer
  - With the 'Select' button, run the appropriate processing recipe, log to a file if desired
  - Note actions in logbook

===== Unloading your samples =====

DO NOT LEAVE THE LOADLOCK VENTED LONGER THAN 5 MINUTES

  - On the 'Load' page, click 'Unload' to unload the wafer
  - Click 'Vent' loadlock
  - The system will go through 2 flushing cycles, then vent
  - Remove substrates (ALWAYS WEAR GLOVES!)
  - Pump down loadlock as described

===== When your sample is finished =====
DO WRITE YOUR FINDINGS IN THE LOGBOOK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

===== Troubleshooting =====
Often there are problems with pumping or the communication between the machine and the software. 

A procedure that solves many of these problems (//not to be followed when a problem occurs during wafer transfer!//):

*Click "Abort" on the load page
*Close software and shutdown computer
*Switch off machine (red **push**button at the right of the machine)
*Switch on machine (green push button at the right of the machine)
*Restart computer and start software
*Check whether substrate cooling is on (august 2010: because cooler is defect, read: "check whether tap water is running")
*On the load page, start chamber and loadlock rotary pumps.
*Evacuate chamber and loadlock (even when you desire to vent the loadlock!)

After these steps, the software and the machine should be in normal operation

====== Etching rates ======
^ Material^  Date   ^ User ^ Thickness ^ Etching time  ^ Power ^ Pressure ^ Gasses [sccm] ^ Etch-Rate ^  
| MoGe    | 01.03.2012 |       | 19.4    | 30s           | 100W  | 75mtorr  | CF4(30) / Ar(10)        | 0.65 nm/s |
| SiO2    | 15Jan2018 | Douwe | multiple| multiple      | 150W  | 30mtorr  | O2(3) / Ar(10) / CHF3(15) | 16nm/min (0.27nm/sec) |
| PMMA 950K  | 15Jan2018 | Douwe | multiple| multiple      | 150W  | 30mtorr  | O2(3) / Ar(10) / CHF3(15) | 74nm/min (1.23nm/sec) |
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To ash PMMA/MMA double layer resist and/or clean your SiO2 chip from any other organic crap, use 20 min in 30Torr O2 plasma (30sccm flow, 16'C sample temp.)