The E-beam evaporator is used to deposit any metal or dielectric on to a substrate.
This is the specialty of the E-beam over the thermal deposition system. The depositions
made with the E-beam evaporator are high purity and they have good adhesion.

The electron beam evaporator has an electron gun which is operated at a very high
voltage (10 kV) and current (~1 A). When a tungsten filament within the ebeam system
emits electron from thermionic emission and it produces an electron beam which hits the
metal on the pocket. The metal acts as a resistive load gets hot from the high voltage and
current. The beam curls up to 270 degree in to a crucible which loads to thermal
evaporation of the target and direct beam of material towards the substrate which is at the
top of the chamber. The whole process is done under vacuum.


Apparatus Description:

The Airco Temescal Electron Beam evaporator has a chamber which can reach a high
vacuum pressure and can deposit any metal or dielectric. The chamber can be pumped
down to 2 x 10
-7
torr.

Automatic Valve Controller:

The E-beam Evaporator has an automatic valve controller AVC-485 which controls the
vacuum system. It has two operating modes, Automatic and Manual modes. In our
laboratory, we use the automatic mode for which the procedure is explained below.

XYS-8 Sweep Control:

The XYS-8 Sweep Control has the ability to adjust the beam in either a longitudinal or
latitudinal position. In general, the controls are roughly already set correctly.
Note: The Beam position for both longitudinal and latitudinal positions should be at the
center and the sweep should be turned fully anti-clockwise.

High Voltage Control:

This part contains interlocks and indicators which will allow the E-beam to turn on the
high voltage. 1.

The Power ON indicator will glow when the power to the E-beam is given via
the power supply.
2.

The Door indicator will glow when the three doors of the power supply unit is
closed properly, Caution: Do not turn try to close the doors when the key is
turned to ON position in high voltage control unit.
3.

The Air Indicator will glow when the air is supplied to the system within the
range of 80 to 100 psi.
4.

The Vacuum tank and Vacuum gauge indicator will glow once the chamber is
pumped down to the operating pressure.
5.

The PC cards and keylock will turn on once all the above interlocks is
released and the key is turned to the ON position from OFF position.
Note: The Key should be turned to ON position only at this point when all the
indicators glow.

Gun Control Unit:

The gun control has some interlocks which will allow the Filament to turn ON.
1.

The Auxiliary is provided to the user or the customer by the manufacturer to have
an interlock if needed.
2.

The Gun water interlock will release and the indicator will turn on when there is
sufficient water to the filament and has the required temperature.
3.

The Focus indicator is turned on when there is sufficient current flowing and the
beam position is generally correctly set already.

Note: The Emission current knob should be rotated to fully anti-clockwise direction and
the beam position should be at the centre.

Deposition Monitor:

The Thin film monitor should be programmed according to the metal used. The density,
Z ratio and final thickness should be set for each type of the metals or dielectric used.
Note: There is table near the system which has the density and Z-ratio values for various
types of metals and dielectrics which are typically used.

Ion Gauge Controller:

The Ion gauge controller is used to continuously monitor the chamber pressure and
display the value in torr. The set points are already set in the system, so do not change
them.

CV-8 Power Supply:

The power supply is connected to the E-beam with a high voltage cable which has the
three phase voltage supply. Check whether the three doors are closed properly before
starting to use the system.
Note: If you leak water or an oil leakage, you will hear a weird nose.
Vacuum System:

The Airco-Temescal CV-8 system has a fast pumping high vacuum system. It contains a
dual stage mechanical pump and a CTI- Cryogenics cryo-pump. The mechanical pump is
used to get to the acceptable pressure where the cryo-pump can start pumping which
usually is about 10
-3
torr. Our cryo-pump starts pumping at 10
-3
torr and the cryo pump
starts it can create a vacuum as low as 2 x 10
-7
torr. (Within half hour or so).

Coating Procedure:

1.

If the chamber is already pumped down, press STOP in the automatic valve
control so the pumping will stop and after a few minutes press VENT then the
chamber will vent to ATM completely. Wait till the pressure inside the chamber is
completely vented and the reading shows ATM which is the atmospheric
pressure. There is an interlock, if the pressure is not high enough the lid will not
go up.

2.

Once it shows the ATM reading, turn the knob to raise which is located at the
front of the door and use both hands to press the green button which will raise the
chamber. Press until you see the holders for the substrate.
Caution: Do not touch the chamber while raising it.

3.

Place the metal which is to be deposited in to the graphite crucibles, if they are
empty or low place more in the pockets directly.

4.

Wear gloves and place the substrate on to the holders carefully and place the pins
carefully on top of the substrate to hold them. Place them slowly as you can
break the substrate as it will be snapping them quickly.

5.

Now, lower the chamber by turning the knob to lower and push the two green
buttons gently so the chamber is lowered.
(Check to make sure the thin film oscillator crystal is not in error or xtal fail
before closing)

6.

After the chamber is lowered, press the START button on the automatic valve
control which should start the roughing pump. Note: It is always good to check
whether the roughing pump is connected to the supply. Beware the roughing
pump is noisy and it will start with a sudden sound. The Hi-vac valve will be
opened when the pressure is acceptable and the rough and fore valves will be
closed automatically when the cryo pump starts pumping on the chamber.

7.

When the Ion gauge shows the operating pressure 10-6 10-7 torr in its display.
You can start coating the substrates.
8.

After the chamber reaches the operating pressure, turn on the key to the ON
position in the high voltage control. Press the HV ON switch so that the high
voltage is applied. Turn the voltage adjust knob slowly to a sufficient voltage ie.,
10kv

9.

Now, turn on the GUN FIL ON switch so that the filament is turned on. Before,
applying the emission current check whether the switch is on the emission current
and not on the side of filament current.

10.

Turn on the Emission control knob slowly till you see an arch which is clearly
hitting on the metal. You could watch the beam using the glass window on the
chamber. It will be Blue with pink glow
Caution: The Emission current should not be beyond 1.2 A at any point.

11.

Switch the motor to the run position and use a nominal speed to run the motor.
Shutter will be closed at this point, after a few seconds wait you may close the
shutter and the deposition will start on the substrate. You can monitor the
thickness of the coating on the deposition monitor. Close the shutter when you
reach the thickness level you desire.

12.

Reduce the emission current to zero slowly and stop the motor.

13.

Switch off the Gun filament by pressing the GUN FIL OFF.

14.

After a few seconds wait, turn the high voltage off by pressing the HV OFF.

15.

Turn the key to off position.

16.

Now press STOP in automatic valve control and after few minutes press VENT
and wait till the chamber is vented to atmosphere.

17.

Now turn the knob to Raise, after the chamber is at atmosphere and push the
green buttons to lift the chamber.

18.

Take the coated substrates carefully out of the holders.

19.

Close the chamber by turning the knob to the Lower and pushing the green
buttons.

20.

Once the chamber is lowered press the START button in the automatic valve
controller.
Note: check whether the roughing pump is connected to power supply before
pressing the start button