Edwards Auto 306 DC and RF Sputter Coater - Berkeley Microlab

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Edwards Auto 306 DC and RF Sputter Coater
1.0 Title
Auto 306 DC and RF Sputter Coater
(edwards)
2.0 Purpose
The Edwards system sputters metal and dielectric materials
3.0 Scope
Films are deposited by bombarding the target material with high-energy ions from a plasma. The films
deposited by this method are uniform in thickness and capable of covering areas usually shadowed by
other deposition methods.
The Edwards system consists of two parts:
► Deposition chamber, vacuum system and control panel
► DC and RF power supplies and MFC control panel
Inside the deposition chamber are two magnetron guns (DC on right, RF on left, a substrate holder (6inch
standard, with 4-inch adapter plates), a thermal couple and a substrate heater. Maximum
temperature for the substrate heater is 250ºC. Do not exceed this value. The control panel controls the
vacuum, the rotation of the substrate holder and heating of the substrate. One mechanical pump is
installed for rough pumping and one turbo pump for fine pumping. A crystal monitor is installed in the
system but not currently configured for use.
A DC and RF power supply provides the power needed to generate plasma in the deposition chamber.
4.0 Applicable Documents
Revision History
Description of a basic vacuum system:
http://microlab.berkeley.edu/labmanual/chap6/vacuum.pdf
Vendor manuals: Edwards Auto 306 DC and RF Sputter Coater. Auto 306 Accessories: Plasmaglo, DC
Sputtering, Single Bar Glow Discharge, Gold Plated Target, SEM Specimen holder
and Auto Gas Bleed Kit. Auto 306 Accessories: Workholder and Heater Accessories.
Auto 306 Accessories: Rotary Workholder. Advanced Energy MDX 1.5K Magnetron
Drive. Advanced Energy MDX 1.5K. VM 700-1000-1500 Instruction Manual.
Vendor materials on web: http://www.bocedwards.com/pdf/planar.pdf,
http://www.bocedwards.com/pdf/CoatingSystems_Components.pdf,
http://www.bocedwards.com/pdf/auto306em.pdf
5.0 Definitions & Process Terminology
5.1 Deposition Chamber: Contains DC and RF magnetrons, wafer holder, crystal monitor (not
installed yet) and heat lamp. The door has a magnetic bearing and users should gently close the
door without adding forces on it to assure good seal of the chamber.
5.2 Control Panel: Allows you to vent and pump the chamber.
5.3 DC power Supply: Middle of the equipment rack to left of deposition chamber. OFF unless
process interlock on.

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5.4 RF Power Supply: Bottom of the equipment rack to left of deposition chamber. OFF unless
process interlock on.
5.5 Workholder Control: Controls the rotation of the wafers.
5.6 Crystal Monitor (not yet configured): Monitors the evaporation rate by correlating deposited
metal thickness to the amount of deviation from its original crystal resonant frequency.
5.7 Sputtering Materials: Targets available from Microlab: Ag, Al, Co, Cr, Cu, In, ITO (90/10%), Ni,
Pd, SiO2, Ti, W. Members may supply their own targets for use in this system after getting
permission by e-mailing Edwards at silicon.eecs.berkeley.edu and requesting a new sputter
material. Gold, palladium, platinum and other precious metal targets will no longer be stocked by
the Microlab after the current inventory is exhausted.
5.8 Target: Diameter: 7.5 cm. Standard thickness: 6 mm. Can order from Super Conductor
Materials, Inc. Dielectric materials and poor thermal conductors should be ordered indiumbonded
to a 1/16” (~1.5 mm) copper backing plate.
6.0 Safety
6.1 Read all relevant instructions before you operate any accessories.
6.2 Surfaces within the AUTO 306 may hot. Do not touch surfaces without cooling first.
6.3 Intense light will be emitted from the plasma.
6.4 Observe all safety precautions when you come into contact with dangerous substances which
have been used with the evaporation materials.
6.5 Wear clean lint-free gloves when you handle components in the chamber to prevent
contamination of the evaporation materials and its accessories.
6.6 Do not add extra forces when you close the chamber door. It will damage the magnetic bearing.
6.7 Metal dust is a hazard. Never use compressed gas to clean the chamber. A house vacuum drop
is available to the right of the chamber.
7.0 Statistical/Process Data
The following recipes (parameter settings/dep rates) provided by Hellman group (Physics) can be used
to sputter different films in the Edwards machine (see Tables below (data dated 10/17/06). Please note,
all these recipes use power settings below the cut off limit (350W

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8.0 Available Process, Gases, Process Notes
Pumping Speed: < 10 min. to reach process pressure.
Available Targets: Al, Cr, Cu, ITO, Ni, SiO2, Ti, W, Ag, Pd, Co
Precious metal targets, such as gold and platinum are not stored by the edwards. Precious metal
targets are available for checkout from the Microlab office.
Maximum power for the Edwards for any bonded target is 350W.
Note: Maximum allowed power density with dielectric and ITO targets is ~2 W/cm 2 (100 W).
For ITO deposition, films with the best conductivity and transparency are obtained with a power
density of 1 W/cm 2 for DC sputter (~ 50 W) and 1.5
W/cm 2 for RF sputter (~ 75 W).
Labmembers are cautioned against comparing the RF or DC power setting of a specific tool in the
MIcrolab to the power setting published in some reference for some other tool. Most references do not
provide any critical tool geometry information (target size and distance from source). Power density -
not the absolute setting of the power supply - is the significant variable for determining deposition rate.
For example, on the Randex (another general use sputter tool in the Microlab) the target size is 5”
diameter, and the maximum allowable power is 1000 W – which also corresponds to a target power
density of about 7W/cm 2 .
Note: Lab members can use process conditions noted in Section 7.0, as a good starting point for their
own process.
9.0 Operating Procedure
9.1 Enable edwards on WAND.
9.2 Check that the “Water Cooling” and “Control Cabinet” green interlock lights are ON. Report fault
if not. The “Vacuum System” green interlock light should also be ON if the system was properly
left in standby mode and pumped down by the previous user.
9.3 Vent the chamber (press SEAL and then VENT). The vacuum interlock will turn off shortly after
the system output reads atmospheric pressure. It will take a little longer for the chamber to be
able to be opened.
9.4 Place targets in the RF (front left) or DC (back right) magnetrons.
Note: DO NOT TOUCH THE TARGET WHEN IT IS HOT, IMMEDIATELY AFTER
PROCESSING WAFER/S. THIS CAN RESULT IN INJURY AND/OR TARGET
CONTAMINATION (SURGICAL GLOVES CAN EASILY MELT ONTO THE TARGET
SURFACE).
9.4.1 Open the shutter for the appropriate magnetron. A manual lever on the left hand side of
the chamber operates the RF shutter and the control unit to the right of the chamber
operates the DC shutter (SS1 button).
9.4.2 Lift off the target shield cylinder surrounding the magnetron. Care should be taken not to
hit the inside of the chamber as this is being done. The work-holder may need to be
rotated and the 4”insert rings removed in order to remove the DC cylinder from the
chamber. Sometimes it works best to remove the cylinder through one of the wafer
holder 6” holes.
9.4.3 There are currently two types of target clamp rings used on this tool, the old and the new
style clamps. The old design still used on the RF gun is a copper clamp that needs to be
tighten down by several screws (torque wrench). The new style clamp is a spring loaded
ring that engages three stationary pins (screws) to hold the target down on top of the
magnetron sputter gun assembly.
9.4.4 Follow the instructions below for Installing or removing a target in Edwards machine.
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Old Style Screw Holes Ring
Unscrew and remove the copper clamp ring on top of the magnetron sputter gun and
place the target on the top. Use caution when placing magnetic targets onto the sputter
gun. There are strong magnets in the gun that will attract the target and this is a pinch
hazard. Replace the copper clamp ring back in place and screw it down in a
diagonal/star pattern - a 3 mm metric Allen wrench and a 5” lb. torque.
New Style Clamp Down Ring
Rotate the spring loaded copper clamp down ring, counter clockwise to remove it from
top of the DC magnetron sputter gun, shown in Figure 1. Place the desired target on top
of the gun, Figure 2. Use caution when placing magnetic targets onto the sputter gun.
There are strong magnets in the gun that will attract the target and this is a pinch
hazard. Replace the spring loaded copper clamp ring back in place by rotating it
clockwise to engage the stationery pins on the magnetron sputter gun, Figure 1.
Note: Clamp rings are thickness specific can hold 1/4" and 1/8" thick targets. The clamp
ring currently available at the station caters 1/4" targets, therefore proper backing plate
needs to be ordered with expensive sputtering material that would otherwise be too thin
(expensive) to meet above specification, hence, backing plate + target material = 1/4".
9.4.5 Clean off the sputter gun top surfaces to remove any materials from previous runs
(Scotchbrite pads and IPA work well for this, wipe with clean-room wipe and IPA, pads
are provided in the target storage area above the tool). Pads should remain with the
machine at all times. Inspect the target clamp and shield cylinder for excessive material
build up. Report a fault if either needs a thorough cleaning.
9.4.6 Place the cylinder back around the magnetron. If you have the standard target thickness
of 6 mm, the smallest slot should be used for the RF target shield and the middle slot
should be used for the DC target shield. A standard 6 mm thick target will have 5 mm
spacing for the shield for RF sputtering and will have 3 mm spacing for DC sputtering. If
your target is a different thickness consult the Edwards Auto 306 DC and RF Sputter
Coater manual in the Microlab office. Magnetic materials need to be much thinner (1-2
mm) and should use a Cu backing plate to obtain the overall desired thickness.
9.4.7 Close the shutters once the target is in place. If a target is not being used, the cover
should remain over the shield.
9.5 Once the target is in place, check to make sure that the wafer holder can rotate freely - the
thermocouple needs to clear the rotating holder and can easily be moved when changing the
target. Place the wafers in the substrate holder, using the 4-inch wafer converters if necessary.
9.6 If the small cylinder vacuum cap in the front right of the chamber has popped off, replace it in the
correct position.
9.7 Close the chamber door and press CYCLE to evacuate the chamber. Pressing cycle evacuates
the chamber without enabling the process interlock.
9.8 When the vacuum is sufficient to begin the sputter process, the PROCESS button will light up on
the vacuum control panel. Press PROCESS to begin the sputter process. Once the process
interlock is enabled, the gas flow controller and the DC and RF power supplies are enabled.
Start flow of the Ar/N/O2 gases depending on process parameters.
9.9 Mass Flow Controller (MFC)
9.9.1 Enable Gas 1 (AR) or Gas 2 (O2) by toggling the pneumatic toggle switches just above
the Brooks Controller. The Left toggle switch is for Argon and the Right toggle switch is
for Oxygen/Nitrogen. This opens the pneumatic valves only. Either Nitrogen or Oxygen
may be selected by turning the valve below the vacuum control panel.
9.9.2 Set MFC flow at front panel of the Brooks controller. Press the “Channel Selection”
Key until you see “>” symbol after 1 or 2, i.e. “1>” = Gas 1 is Active channel.
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9.9.3 Set the desired flow by pressing the “Up” or “Down” arrow keys to your desired flow
setting. The double up arrows increments by 1’s and the single up arrow button
increments by .05.
9.9.4 Press “Enter” (the set-point will not be entered until you press enter).
9.9.5 The controller display will automatically cycle back to flow reading within a few seconds.
You should see gas flow at this time. You must be in “Process” mode on the Edwards for
gas flow.
Note: PLEASE DO NOT ADJUST ANY OTHER VALUES OTHER THAN GAS SETPOINTS
ON THE BROOKS CONTROLLER.
9.10 Adjust settings for appropriate power supply. Please see applicable documents in Section 4.0 if
process parameters are not already known for your material or consult superuser/Microlab staff.
Process data will be supplied in this document once materials have been evaluated.
9.11 DC Sputtering – AE MDX-1.5K
9.11.1 Press SETPOINT and adjust the set point using the level knob.
9.11.2 Press ACTUAL until watts are shown. Do not exceed 350 Watts for unbacked metal
targets. Targets attached to a backing plate should be limited to 300 Watts or less.
9.11.3 Do not adjust RAMP – the knob should be locked.
9.11.4 Turn on the power supply and look for plasma – color will depend on material being
sputtered.
9.12 RF Sputtering – AE RFX-600
9.12.1 Hold down SETPOINT while adjusting the LEVEL knob to set the sputter power. Do not
exceed 350 Watts for metal targets. Dielectric targets and targets attached to a backing
plate should be limited to 300 Watts or less. Use caution with power settings for thermally
sensitive materials.
9.12.2 Make sure that the auto-tuner is set to AUTO.
9.12.3 Turn on the power supply and look for plasma – color will depend on material being
sputtered.
9.12.4 Tips for igniting the RF plasma
9.12.4.1 Set the Ar pressure to ~20 mTorr and turn on the power supply. When the
plasma ignites the Ar pressure can reduced to the desired pressure.
9.12.4.2 Start with a metal target in the DC gun and ignite the plasma. (The shutter
does not need to be opened.) Turn on the RF power supply. The DC power
supply may be turned off once the RF plasma has ignited.
9.13 Start rotating the wafers. Open shutter and start deposition time.
9.14 Once done sputtering, close the shutter, turn off power supply, and then stop the wafer rotation.
Set the MFC to zero flow and press CYCLE to evacuate the process gas from the chamber. If
the process interlock turns off while sputtering, you will need to extend the time delay for the
interlock. See the Troubleshooting Section for more information.
9.15 Press SEAL and then VENT if the process interlock is still enabled. If the time delay set point has
passed and the process interlock is disabled and only VENT needs to be pressed. Make sure
that the chamber has sufficient time to cool down before venting.
9.16 Wait for the chamber to come up to atmospheric pressure and remove wafers from the holder.
System may be hot inside deposition chamber if sputtering times were long.
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9.17 Repeat from 0 if additional wafers need to be processed. Otherwise proceed to 9.18.
9.18 Open appropriate shutters and remove target(s). Replace ALL covers and close the shutters.
Replace vacuum cap. Targets should be returned to their appropriate storage container and
never be left in the chamber.
9.19 Once all wafers and targets have been removed, close the chamber door and evacuate the
system by pressing CYCLE.
9.20 Once the system is pumped down, disable the equipment on wand and provide the following
information in the comment section: material sputtered, gas type and flow rates, DC or RF power,
and deposition time (for desired thickness if known). If a previous user had left a target in the
system, please make a note.
10.0 Troubleshooting Guidelines
10.1 Process interlock shuts off.
If the time delay set point is too short and the process interlock disables before you are done
sputtering, you can adjust the time by going into the set point-relay menu.
10.1.1 Press NO for main menu, scroll to set point-relay and press YES.
10.1.2 Scroll to time delays and press YES.
10.1.3 Scroll to time delay 7 (if not already there).
10.1.4 To adjust time, press yes and a blinking B should be seen. Using arrow keys, set the first
digit of the desired time and press yes. Set the second digit and press YES or press YES
again (while B is still blinking) to go the minute/second display. Set to minutes (M) or
seconds (S) and press YES to set new time.
10.1.5 Once the new time is set, press NO to exit menus until you reach the main menu. Select
Process Sequence and press YES to go back to the normal screen.
10.1.6 Gases are not flowing. If all the appropriate switches are open and no gas is flowing
check to make sure edwards is enabled.
10.2 VOLTS ERR is displayed on the vacuum control panel.
This error is displayed when the high vacuum (Penning) gauge has a flake in it. The vacuum
controller will not let you enter the process mode if this condition exists. File a fault on the wand
to have the gauge cleaned by the process staff.
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11.0 Figures & Schematics
Figure 1 - Copper Clam Ring With Springs Holding Down The Target
Figure 2 - Target on DC Magnetron Sputter Gun
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Gas Selection Box
DC Power Supply
MFC Controller
Emergency Off Button
Distribution Panel
Matching
Network
Controller
Equipment Rack
RF Power
Supply
Rotary Workholder Drive
Workholder
Figure 3 - Edwards Auto 306 DC and RF Sputter Coater
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Deposition Chamber
Magnetron Source
Control Console
Control Cabinet
Reactive Gas
Selection Box

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RFX - 600
Status LEDs Reflected Power Indicator
Right
Left Digital
Digital Meter
Meter
Output
Enable
Switches
Figure 4 - Control Panel
Output
Level
Control
Power
Display Setup
Switches Regulation Setup
Set Point Enable
Remote
Control
Switches
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Digital
Indicator
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Setpoint Controls
ENTER
Figure 5 - Distribution Panel
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0152E
Channel
Selection
Valve
Open/Close
(not used)
Remote
Control
Power

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Figure 6 - DC Power Supply
Figure 7 - Rotary Control Panel
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Figure 8 - Heater Control Panel
Figure 9 - Shutter Control Panel
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