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Description

The Ion Beam Etcher has a collimated monochromatic broad-beam ion source (Kaufman type) that can be used for ion etching / ion milling. The beam diameter is 4 cm. Working pressure is 3-4 e-4 mbar. The maximum beam current is 10 mA and the maximum energy is 1500 eV. For resist processing typically low energies are used to avoid damage to the imaging resist.

The system is equipped with a loadlock with a (sputtering gun, removed jan 2012) knudsen cell so that a deposition step can be performed immediately after etching (a so called self aligned process). The substrate table can be tilted and can rotate in the tilt plane.

Manual Ion beam etcher

Mounting sample on holder

If rotation is required (to avoid 'ears') use the holder with the rotation option.
Glue the sample on the holder with silver paint (Dry for ~10 mins)

Insert sample

Turn off the Penning pressure gauge, by pressing HV.
Press TM to switch to the Pirani pressure gauge.
Turn off the turbo (set switch to down position)
Close valve to the rotary pump (attached to the turbo).
Switch to the DM pressure gauge.
Wait until the turbo has slowed down (you can let in some gas to speed this up, 1e-1 mbar max).
Vent the chamber to atmospheric pressure and close venting valve.
When the chamber is at atmospheric pressure, check if shutter is closed and open the chamber.
Slide the sample holder onto the cooling stage and close shutter.
Check rotating table (max 1 volt - although 0.5 is usually enough, current 20mA or so)
Close the chamber.

Pumping down

Open the valve to the rotary pump (attached to the turbo).
Flip TP switch up to start the turbo pump.
At 10 mbar switch to TM pressure gauge.
Make sure green valves is closed, set black valve to ““IBE”” and open needle valve. Never turn this to “RIE”, because this is an unconnected conduct, which will cause air to flow into the Argon conducts.
Wait (~30 mins) until pressure is <1.0e-5 to 1.5e-5 mBar. The turbo pump should now be at maximum speed.

Etching

Cool with N₂ if needed (Resist can become too hard to remove if not cooled, especially if you etch longer than 4 min).
- Check if N₂ barrel needs to be refilled.
- Attach Hose
- close lit of N₂ barrel
- close gas outlet (warning: danger of explosion if all outlets are closed) and wait
- open liquid outlet
- the tubes should fill and due to the cold condense and freeze on the outside (if you shake the barrel a bit, the N₂ heats up and the barrel should pressurize faster).
- When the N₂ sputters out the exhaust, close the liquid outlet.
- open gas outlet. (You can optionally open the lit).
Turn on power to rotating table (1 volt), otherwise the rotation might not work at low temperatures.
Note the base pressure in the Logbook.
Open green valve
Set Argon pressure to 2,5e-4 to 4.0e-4 mBar with program on the computer
- If you can't find the computerprogram to do this, switch the screen to the IBE computer.
- If you are on the right computer but the software seems to be closed, you can find the program by clicking on the terminal icon on top of the desktop. Type 'cd MFC/code', press 'enter', type 'python debiantest.py' and press 'enter' again. Enlarge the appearing window!
Turn on main power for ion beam (watch safety fuse)
Select recipe (#10)
- press 'select recipe'
- press '+' and '-' to select the right recipe on the LCD.
- press 'enter'
- press 'view recipe'
Make sure the ion canon shutter is retracted (black vertical knob on the left) and doesn't touch the sample holder.
Press “source” on control panel (this step is optional, it is done automatically once you do the next step)
To start etching press “beam” on control panel
Elapsed time is shown on display. You must stop the system manually once the desired etching time is reached.
Press “source” to stop
Turn off main power for ion beam.
Turn off rotating table.

When done

Let ion gun cool by increasing Ar flow (1e-2 mbar, 2 min)
If you cooled your sample, let the sample warm up for at least 15 min (08-04-21: Or do 5 min and do another 10 mins at 1 bar) while pumping (this to avoid possible pollution of oil or other things on your priceless sample).
Close green Argon valve.
Let the Argon be pumped out the conduct and set the Argon needle valve closed.
Set black Argon valve to neutral
Turn off turbo pump
Turn off rotary pump
Wait until turbo pump has decelerated
Vent the system slowly with the “vent” switch (start with 1 sec)
If you cooled with N₂, you need to let your sample stay inside the lock at close to 1 bar (~10 mins) to let the sampleholder warm up. As long as it is below 0, Ice may form, once you remove it.
Remove sample holder
Pump chamber down for a few minutes with rotation pump (no turbo).
Remove sample, clean sample holder with acetone and IPA.
Shut down rotation pump if you are the last person on the day.
Fill in the log sheets. COPIES OF THE LOG SHEET ARE HERE: ibe-logbookv2.xls.

Advanced options

Pressure Gages:
- (10-1000 mBar) The high pressure gage 'DM' can be selected manually.
- (Below 10 mbar - “pirani”) you can switch to 'TM'.
- (High Vacuum - “penning”). The system will (should) automatically switch to the lowest pressure gage 'PM'. You can turn off the high vacuum pressure gage 'PM' “penning” by pressing 'HV'.
- You can see which pressure gage is active at the display indicator direcltly above it.

ibe-logbook.xls

Pressure gauges

Pressure Gauges:
- (10-1000 mBar) The high pressure gage 'DM' can be selected manually.
- (Below 10 mbar - “pirani”) you can switch to 'TM'.
- (High Vacuum - “penning”). The system will (should) automatically switch to the lowest pressure gauge 'PM'. You can turn off the high vacuum pressure gauge 'PM' “penning” by pressing 'HV'.
- You can see which pressure guage is active at the display indicator directly above it.

Pressure control unit: Leybold and Hereaus Combivac CM33.
The pressure control unit will switch automatically between the different pressure sensors.

DM (Capacitance gauge, 1000 to 10 mbar): Leybold CM1000
TM (Pirani gauge , 10 to 10e-3 mbar): Thermovac TR 216 Leybold
PM (Penning gauge , 10e-3 to 10e-8 mbar): Penningvac PR36

Etching rates

Material	Date	User	Etched Thickness	Etching time	Recipe	Gas	Rate
Al	20080708	Jorina	20 nm	360 sec	10	Ar, 3.0e-4 mbar	0.056 nm/sec
Al	20151007	Timothy	9.9 nm	180 sec	10	Ar, 3.0e-4 mbar	0.055 nm/sec
Au	20090518	Christianne	90 nm	110 sec	10	Ar, 3.0e-4 mbar	0.820 nm/sec
Au	20111206	Boltje	19.7 nm	30 sec	10	Ar, 4.0e-4 mbar	0.660 nm/sec
Au	20120404	Boltje	12.6 nm	30 sec	10	Ar, 3.0e-4 mbar	0.420 nm/sec
Co	20110105	Boltje	22.3 nm	150 sec	10	Ar, 3.2 e-4 mbar	0.149 nm/sec
Co	20111207	Boltje	33.6 nm	168 sec	10	Ar, 4.0 e-4 mbar	0.200 nm/sec
Co	20120404	Boltje	7.4 nm	30 sec	10	Ar, 3.0 e-4 mbar	0.247 nm/sec
Cu	20110112	Boltje	41.8 nm	70 sec	10	Ar, 3.2 e-4 mbar	0.597 nm/sec
Cu	20111206	Boltje	23.1 nm	42 sec	10	Ar, 4.0 e-4 mbar	0.550 nm/sec
Cu	20120404	Boltje	9.3 nm	30 sec	10	Ar, 3.0 e-4 mbar	0.310 nm/sec
LCMO(L401)	20060621	Christianne	40.7 nm	230 sec	10	Ar, 2.5e-4 mbar	0.313 nm/sec
LCMO(L558)	20091002	Christianne	20 nm	240 sec	9	Ar, 2.5e-4 mbar	0.083 nm/sec
LCMO(L566)	20090520	Christianne	10 nm	30 sec	10	Ar, 3.0 e-4 mbar	0.330 nm/sec
MoGe	20120403	Boltje	3.5 nm	30 sec	10	Ar, 3.0e-4 mbar	0.117 nm/sec
Nb	20050311	Chris	50 nm	232 sec	10	Ar, 2.5e-4 mbar	0.215 nm/sec
Nb	20101409	Laurens	100nm	1080 sec	10	Ar, 3.2 e-4 mbar	0.093 nm/sec
Nb	20121114	Stefano	18.8 nm	200 sec	10	Ar, 3.2 e-4 mbar	0.094 nm/sec
Nb	20140926	Boltje	28.3 nm	420 sec	10	Ar, 2.9 e-4 mbar	0.067 nm/sec
NbN	20050215	Olaf	51.3 nm	352 sec	10	Ar, 2.5e-4 mbar	0.146 nm/sec
Ni	20110117	Boltje	15.6 nm	80 sec	10	Ar, 3.2 e-4 mbar	0.195 nm/sec
Py	20130603	Boltje	19.2 nm	120 sec	10	Ar, 3.9 e-4 mbar	0.160 nm/sec
Py	20131120	Henk	32.4 nm	150 sec	10	Ar, 3.0 e-4 mbar	0.216 nm/sec

Nb 20050311 based on 7:30 sputtering in UHV, 220 mA, 4 ubar, 0 angle, 258 A Xtal

Deposition rates

Material	Date	User	Process parameters	Measurement	Time	Result	Rate	Notes
SiO₂	20120907	Boltje	1090 ^oC	X-ray	15 min	15 nm	1 nm/min
SiO₂	20140321	Boltje	1090 ^oC	X-ray	30 min	140 nm	4.67 nm/min

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