Download VARIAN 3125 Automatic Deposition E-beam Evaporation Procedure

VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
E-beam power supply
Vacuum chamber
Electronics Rack
Varian 3125 e-beam deposition vacuum system
Introduction The Varian 3125 system includes the main vacuum chamber and associated vacuum pumps and
valves, the electronics rack, and the e-beam high voltage power supply. The system uses a cryogenic vacuum pump
to reach high vacuum levels.
In the automatic mode the system is interlocked to prevent:
1) Accidental venting of the vacuum chamber with the high vacuum gate valve open
2) Application of the high voltage to the e-beam if the vacuum chamber is not at sufficient vacuum level
3) Excessive e-beam emission current which could cause catastrophic failure of the system
Under no circumstances should the system ever be operated in a “manual” mode
File: Word/Procedure-Varian Automatic Deposition
VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
System check
1. If the status light is green, the system is available to use. If the status light is yellow, the system is in use by
someone. If the status light is red, the system is down for repairs or regeneration.
2. Verify foreline pressure on Varian 845 ion gauge controller, located in the electronics rack, is zero. If not
zero, cryo pump will need regeneration – call lab manager.
3. Check cryopump temperature on gauge in electronics racks Notify lab manager if temperature is above 30K
4. Verify circuit breaker on the Temperature Controller 968-1203 is off. The circuit breaker is off when there is
no display on the meter
Status Light
Foreline pressure
meter - Varian 845
controller
Heater control –
circuit breaker must
be off and no display
visible
Automatic pump
down controller
Varian Process
Control 980-6100
Shutter and fixture
Rotation controller
Granville-Phillips
Ion gauge
controller/meter
Kronos
Deposition
controller
Chamber
pressure in
torr
Cryopump
temperature
Meter
Varian 3125 electronics Rack
File: Word/Procedure-Varian Automatic Deposition
VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
System operation
1. Turn off ion gauge if not already off
2. Vent chamber by moving the control knob on Varian Process Control 980-6100 controller from pump to
vent. Open nitrogen toggle valve located alongside chamber if not already open. The valve is open when the
toggle handle is vertical.
3. Once chamber is vented to atmosphere the door will open. Close nitrogen toggle valve.
Pump down controller
switch – pump to pump
down the chamber, vent
to vent the chamber
Ion Gauge controller
Kronos deposition controller –
program for each material to
be evaporated
File: Word/Procedure-Varian Automatic Deposition
VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
4.
Replace glass slide on viewport.
Replace 3”x2” glass slide after
each deposition
Inside of front chamber door
5.
Verify proper evaporation materials are loaded into crucible. If not, load proper materials making sure the
correct tag is place on the appropriate pocket position on the front of the chamber.
This photo shows the current materials loaded in pockets 1-4 and must be verified before each deposition
File: Word/Procedure-Varian Automatic Deposition
VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
This is a four pocket crucible - only the pocket in use is visible. To access the other pockets, turn the manual knob attached to
the chamber, located on the rack side of the chamber. Be sure the material matches both the pocket position as shown on the
side knob and the tag on the front of the chamber.
6.
Load parts to be coated on to holder (platen) and place holder into chamber making sure the holder is seated
properly on the rotating ring.
Spring clips hold wafers
Wafers or other substrates are held in place with small spring clips
7.
8.
9.
10.
11.
12.
Turn fixture rotation to “MAN” on the Accessory Control panel located on the electronics rack. Do not
adjust speed. Fixture will begin rotating after a minute or two. Verify rotation. Skip this step if no rotation
is desired. Rotation provides better film uniformity.
Set shutter switch, located on the Accessory Control panel, to “AUTO”. This will allow the shutter to be
controlled by the Kronos Automatic Deposition System model ADS-200.
Position the material to be evaporated into the open position on the e-beam crucible. Note the number on the
side control knob.
Using the Varian 3125 Automatic E-Beam Deposition Chart, program the Kronos Automatic Deposition
System for the material to be evaporated. Each material is listed on the chart attached to the front of the
vacuum chamber.
Push the vacuum chamber door closed and hold closed while going to step #12
Begin chamber pump down by moving knob on Varian Process Control 980-6100 controller from vent to
pump.
File: Word/Procedure-Varian Automatic Deposition
VARIAN 3125 Automatic Deposition
E-beam Evaporation Procedure
13. Allow the chamber to pump down.
14.
15.
16.
17.
18.
19.
20.
21.
22.
Chamber will be pumped by the roughing pump to less than 100
millitorr. At that point the roughing pump will cease pumping, the high vacuum valve will open, and the
chamber will be pumped by the cryo pump.
Wait until chamber pressure is at zero. Then turn on the Granville-Phillips ion gauge by holding the gauge 1
switch until there is a reading on the display. Wait until the chamber reaches 3.0 x 10-6 torr or lower before
beginning evaporation. Ideally the chamber should be allowed to pump over night if time is available. If the
ion gauge does not turn on, wait a few more minutes and retry.
Turn on high voltage power supply (blue cabinet next to chamber). If power supply does not light up, reset
circuit breaker in electrical box CR2 inside pump room just behind chamber.
Verify all interlocks are satisfied (all lights on). Turn on high voltage, wait a few seconds, and then turn on
filament. High voltage meter should read about 7KV. The filament current meter does not work and should
indicate less than zero. Call the lab manager is meters read different.
Press the start button on the Kronos Automatic Deposition System. This will initiate the program to deposit
the material you selected. You will be able to view the evaporation through the viewport. The dark glass
goggles should be used. The e-beam can be adjusted front to back. Be very careful not to move the e-beam
out of the crucible area.
The Kronos will control the deposition rate and will stop the e-beam current when the desired thickness is
reached as programmed.
If a second or third material is required, repeat steps #8 and #9.
When all evaporation is complete, allow material to cool, typically 15 minutes.
Vent chamber by moving control know on Varian Process Control 680-6100 from pump to vent. Make sure
nitrogen toggle is open.
Once chamber is vented, close nitrogen toggle valve and unload.
File: Word/Procedure-Varian Automatic Deposition