Hummer II Sputtering System


Table of Contents

About this Machine

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The HUMMER II performs sputter coating, a cold process in which ions impacting a metal source dislodge metal atoms. The atoms disperse throughout the process chamber to uniformly coat irregularly shaped specimens without thermal damage. Sputter coating produces high quality coatings whose thickness is repeatable and easily controlled. Cold, fast sputter rates require less time, giving you more time for microscope examinations.

The HUMMER II has three operating modes:

  1. Plate Mode – to plate a specimen with a metal
  2. Etch Mode – to remove material from a specimen
  3. Plasma Mode – to clean a specimen or for crosslinking of organic specimens

Any of these three modes can be operated in “Pulse mode” (repeated on-off pattern) to avoid the aggregation of material in localized place and to reduce the specimen heating. Typical process cycle 3 minutes, coat 2 minutes, release to atmospheric pressure 15 seconds.

The HUMMER II uniformly deposits gold/palladium, platinum, palladium, carbon, chrome, copper, nickel, and other metals. Metals, organic and ceramics are uniformly cleaned and/or etched in conjunction with coating.

Machine Safety

How to Get Help

Ask a Manager if you have any questions.

Using this Machine

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This system has the following controls and functions:

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Setup

Verify that the glass vacuum chamber is placed securely in the groove in the baseplate and that the top plate is in position on the chamber top. Make sure that the contact areas of the chamber and gaskets are free from dirt, dust, and other contamination. There may be a light film of silicone vacuum grease present, this is normal.

This system is equipped with a vacuum pump which must be filled with oil prior to operation. There should be 1 ¼ quarts of mechanical vacuum pump oil present. If you look on the back of the system you can see a small oil view port. The oil must be halfway up the port. If not, ask a manager to help you refill it.

Refilling the Oil (a Manager must be present for this):

  1. The oil is added through the rear oval opening of the cabinet through an exhaust port.
  2. Remove the copper elbow marked “oil filling port”.
  3. Using the small funnel and hose, begin slowly adding the oil.
  4. Several inches below the oval opening is a small oil view port. Keep adding the oil until the level is halfway up the oil view port.
  5. Once the correct amount of oil is added, put the elbow back on the exhaust port.

A gas inlet is also provided for the introduction of pure gases (such as argon or dry nitrogen) for more uniform and oxygen free depositions. A regulated tank pressure of 5-15 psi must be applied at the gas inlet. If deposition conditions are not critical for the sample, then the air inlet should be left free for the introduction of lab air.

Operation

Startup - First Pump Down:

  1. First check that all the switches are off, and all the valves are closed before commencing operation with your Hummer.
  2. To place the Hummer in operation, set all controls as follows: ..- Main Power Switch: OFF ..- High Voltage Switch: OFF ..- Voltage Control: O ..- Process Control: MANUAL ..- Vent Valve: CLOSED ..- Pressure Control: DECREASE ..- Mode Selector: DC PLATE
  3. Open the chamber by lifting the top plate or glass cylinder off and place your specimens on the pedestal.
  4. Adjust the pedestal height to place the specimen approximately ¾ - 2’’ from the top plate electrode.
  5. Loosen the pedestal height adjust knob (black plastic nut at base of pedestal rod)
  6. Raise or lower the pedestal as required. Retighten the nut with your thumb and forefinger only.
  7. Install desired electrode in the top plate by turning clockwise until tight.
  8. After installing the electrode, place the top plate on the chamber and turn on the main power switch.
  9. Wait about 15-20 minutes for the initial pump-down sequence to conclude. After than 2-5 minutes should be sufficient. Note: Pump-down is complete when a vacuum reading of 20 millitorr or less is obtained.
  10. For best operation, especially with carbon electrodes, an inert gas (such as argon) should be attached via vacuum hose to the hose connector at the rear of the cabinet, and regulated to a pressure of 5-15 psi.

Plate – General Operation:

Typical operating conditions are as follows:

Gold or Gold/Palladium Deposition:

Carbon Deposition:

To plate specimens,

  1. Set controls as follows, ..- Mode Switch: PLATE ..- High-voltage switch: ON ..- High-voltage knob: 11 ..- Gas Valve: OPEN until vacuum reading is 80-100 millitorr.
  2. It should be noted that the initial appearance of the plasma will cause the pressure in the chamber to rise and fall due to molecular adhesion of water vapor and atmospheric gases. Adjustment of the gas valve is necessary to compensate for these fluctuations until the pressure stabilizes.
  3. The Plasma will appear with a purple-blue glow.
  4. Vary the pressure in the chamber with the fine metering valve to achieve reading of 5-15 milliampheres.
  5. Set a timer to the desired number of minutes.
  6. Turn switch to AUTO setting.
  7. Note, the Plasma will terminate automatically after the number of minutes selected has expired.
  8. Note, if the pulse mode is selected, timer totalizes only the ON cycle.
  9. When your specimen has been coasted to the desired thickness set the controls as follows, ..- High-voltage control: ZERO ..- High-voltage switch: OFF ..- Gas Valve: CLOSED ..- Main Power Switch: OFF ..- Vent Valve: OPEN
  10. Lift the chamber top and remove your specimen from the chamber.

Etch – Typical Operation:

Typical operating conditions are as follows: Metallurgical Specimen:

Biological/Organic Specimen:

To etch specimens,

  1. Set controls as follows, ..- Selector Switch: ETCH or CLEAN ..- High-Voltage switch: ON ..- High-Voltage control: SIX
  2. Open the fine metering valve until the vacuum reading is 50-70 millitorr.
  3. Once the plasma appears, adjust the current to 10 milliamperes or less by using this valve for biological or organic samples and from 10-30 for inorganic samples.

Plasma Processing:

Plasma Processing is utilized for ashing, cleaning, and etching of metals, ceramics, glasses, organics, and composites. This is a chemical-physical variation as opposed to the DC Etching (Sputter Etching) which is a physical reaction by ion bombardment. The specimens are reacted with active species of oxygen, carbon tetrafluoride or other reactive gas. In addition, organic and inorganic coasting can be deposited by Plasma chemical vapor deposition (CVD).

Typical operating conditions are as follows: Ashing – Cleaning – Etching of Organic and Carbon

Etching of Metals, Ceramics, and Glasses

Deposition of Ethylene Polymers

Cross Linking of Organics (A or N2)

To begin Plasma Processing,

  1. Set controls as follows, ..- Mode Selector Switch: Plasma Exc. ..- Main Power Switch: ON
  2. Evacuate the system to 20 millitorr
  3. Increase the Gas Valve to read a pressure of 1 torr
  4. Place the High-Voltage Switch to ON
  5. Increase Voltage Control to produce a current of 20 milliampheres on the current meter.
  6. Process for desired time with desired gas;
    • Oxygen for cleaning, ashing, and etching of organics.
    • Carbon tetrafluoride for etching of metals, ceramics, and glasses. NOTE: Vent Toxic Fumes.
    • Ethylene for deposition of ethylene coatings.
    • Argon or Nitrogen for cross linking of organic surfaces such as TEM and SEM specimens to improve stability to electron beam exposure.

Shutdown

  1. Turn off the main power switch.
  2. Set all controls as follows: ..- Main Power Switch: OFF ..- High Voltage Switch: OFF ..- Voltage Control: O ..- Process Control: MANUAL ..- Vent Valve: CLOSED ..- Pressure Control: DECREASE ..- Mode Selector: DC PLATE
  3. Remove the top plate from the chamber and verify that all specimens are removed from the system.
  4. Uninstall the electrode.
  5. Place the top plate back on the chamber.

Cleanup

Store all chemicals in their rightful place in the lab. Properly clean up the workstation.

Tips and Tricks

Deposition Curve

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Troubleshooting (Managers Only):

| Problem | Possible cause and Remedy | | ————- |:—————————| | No power when main switch is on | 1. Check that line cord is properly connected both at the power supply and at the wall receptacle.
2. Check that circuit breakers are not thrown. Push button in to reset.
| | Power light comes on but pump will not run. | 1. Check that circuit breakers are not thrown. Push button in to reset.
2. Check power connection between pump and rear of power supply.
3. Check that remote switch on extreme right side of pump is in on position. | | Pump operates but no vacuum can be achieved. | 1. Check to see that the seals on the top and bottom of chamber are free from dirt, dust, hair, etc.
2. Make certain that pedestal adjustment nut is tight.
3. Be sure both gas and vent valves are closed.
4. Check all hoses and clamps for tightness including pump ballast valve and knurled lock-ring just below main pumping port hose.
5. Be certain that proper volume of oil is in the pump.
| | System pumps down well but high-voltage light will not come on. | 1. Make certain that auto operation has not been selected with timer set to “zer”.
2. Check vacuum interlock switch for proper adjustment.
3. Be sure that circuit breaker is not thrown. Push button in to reset.
4. Check 6-pin high-voltage connector at rear of power supply. | | High-voltage is on but no plasma can be generated in any mode. | 1. Check to see that pressure is in operating range.
2. Check to see that high-voltage lead from top plate is properly inserted in receptacle provided.
3. Make sure that ceramic high-voltage connector is attached to bottom of pedestal rode beneath base plate.
4. Be certain that ground connection to top plate and to pedestal are properly made.
5. Check to see that electrodes are properly positioned in the top plate.
6. Check 6-pin high-voltage connector at rear of power supply.
| | Plasma can be generated in one mode, but in other modes, current meter is “pegged”. | 1. Check all causes and remedies in the row above.
2. Check to see that no foreign material is shorting an electrode to the annular space shield surrounding the electrode.
3. Make sure that no foreign material is lodged between the pedestal and the surrounding annular sace shield.
4. Be sure that the pedestal, electrode, and space shields are not excessively coated or dirty, especially when selecting etch mode. | | Plasma is present, but no coating can be achieved. | 1. Be sure voltage is in operating range.
2. Make certain that electrodes are serviceable by insuring that they are clean and free of surface contamination.
3. Check to see that the inside of the glass chamber and all fixtures inside the vacuum chamber are clean, to prevent degassing and contamination of the coating.
4. Purge the chamber of contaminating gases by continually bleeding in and pumping out chamber with inert gas (argon).
| | Pulse mode will not work. | Replace the delay relay located at right rear inside of power supply. | | Vacuum gauge will not work. | 1. Check power connection between vacuum gauge and rear of power supply.
2. Check connection between vacuum gauge tube.
3. Replace gauge and tube as matched set.
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Maintenance (Managers Only):

Cleaning: Many component parts become coated with material. The chambers should be cleaned with water and Bon-Ami cleanser. The pedestal and shields surrounding the pedestal and electrode can be removed and scrubbed with steel wool and then washed with detergent and water. Metallic electrodes can be cleaned with acetone or perchloroethylene. Carbon electrodes should be cleaned with steel wool or emery paper.

The exterior of the instrument should be kept clean by wiping with a damp cloth and spray cleaner. Avoid excessive scrubbing on the front panels and controls.

Grease: Thee seals should be kept coated with a very light film of silicone vacuum grease. The electrodes are actually consumed during the coating process and will take on a matte appearance when worn, usually after 100 to 1200 depositions. Disc type electrodes are easily removed by unscrewing directly from beneath the top plate.

Adjustments: The pressure interlock is used to prevent the high voltage from operating unless the chamber is under vacuum; this interlock switch is suspended vertically beneath the base plate and can be seen through the oval opening at the cabinet rear. This switch is an important safety feature and has been adjusted so that the high-voltage is off when the chamber is vented, and on when the chamber is evacuated. A small adjusting screw is provided for this adjustment. Backing the screw out will allow the high-voltage to come on at a higher pressure and advancing the screw will have the opposite effect.

After long periods of use, the packing around the vent valve may become worn and the valve will feel loose. This tightness can be restored by first loosening the jam nut on the valve body located just behind the panel, and then tightening the chrome compression nut located just in front of the panel. This valve should then be repositioned and held in place by retightening the jam nut against rear of the panel.

The vacuum pumps normally don’t require attention other than to check the oil. The oil should be drained and refilled when pressures below 30 mt cannot be achieved with a good quality mechanical vacuum pump oil, a drain cock for this purpose is provided at the front-left corner of the pump. The lower panel should be removed first. Oil capacity is 1 ¼ quarts, be sure to not overfill.

Repairs (Managers Only):

Refer to the following schematics for minor/major repairs,

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