Chemical Mechanical Polisher

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CMP System - Chemical Mechanical Polisher System

Maintenance Request for CMP System

Contact Information:
Faculty Contact:   Aaron Hawkins
Staff Contact:   Jim Fraser
  Student Contact:   Zach Walker

General Description
1. The Chemical Mechanical Polisher (CMP) is used to polish 4" (or 6") wafer by using chemical and mechanical polishing method. It can planarize the wafer which has different material. The following material can be polished by using CMP system:
  1. Silicon Dioxide
  2. Polysilicon
  3. Silicon Nitrite
Operating Instructions
1. CAUTION: Right now, the CMP sometimes breaks wafers it is polishing and/or drops them on the table. Use at your own risk!
2. Things to check before turning on the machine:
  1. Turn on gas flow valve. This is located to the left of the machine on the wall. You will be able to hear when the gas is on.
  2. Turn on water flow valve. This is located directly behind the machine. It will be easy to tell if it is working because there will be water flowing at the wafer pickup area.
  3. Shake up a barrel of slurry (it tends to settle), open the top, and put the slurry flow line into the barrel. This is located at the back right of the machine.
  4. Turn on main machine power switch. This is directly behind the machine. Turning it directly upwards turns on the power. Turning it to the right turns off the power.
3. Turn on the power (Power button on front), log on the software (Username: Seung, Password: Seung)
4. Setup Menu(use these settings):
  1. Activate Pad Conditioner in Auto Mode: Select the check box to activate the pad conditioner for use in Auto Mode (This is done after the Pad
  2. Conditional Enabled and Home Pad Condition)
  3. Pad Conditioner Enabled: Select the check box to enable the pad conditioner for general use on the machine. (This box must to be checked to allow the pad conditioner to work)
  4. Home Pad Conditioner: Touch this button to home the pad conditioner when the machine is started.
  5. Chuck Homing Enable: Uncheck (Usually for square wafer)
    1. Chuck Blow Off Set Point (psi): 20; 30 is the max, when long time polishing
  6. Auto Cycle Chuck Blow Off Time: 5; 7-10, when long time polishing
  7. Wait After Wafer Load: 3 sec.
  8. Control by Temperature: Uncheck
  9. Fluch Chuck after polish: Select the check box to flush the wafer carrier after a polish cycle.
    1. Flush with DI Water for (sec): 3-5
    2. Flush with Air for (sec): 7-10
  10. ViPRR Retaining Ring (Bottom part of the wafer carrier):
    1. Total Area: Wafer area
    2. Offset: Wafer carrier weight (if we keep using the same wafer carrier, we don't need to change this)
    3. Coefficient: Friction coefficient of the retaining ring
    4. If wafer slips off during a polishing process, check the retaining ring (wears).
  11. Wafer Size: 100mm Round
  12. Load station: Hydro Lift
5. Run slurry for a couple of minutes on manual mode when first starting to get the line filled, otherwise it will not immediately flow when polishing!
Recipe
1. Chiller is not currently functional. Please keep polish times around 1 minute to reduce risk of machine damage.
2. Break in Zone
  1. Conditioning pads.
  2. Done for new pad or for pad not being used for long time.
3. Polishing
  1. Time (sec.): Polishing time set point (0-500)
  2. Down Force (psi): Polish down force set point (0-10). At less 1 psi higher than back pressure
  3. Table RPM: Table speed set point
  4. Chuck RPM: Chuck (wafer carrier) speed set point
  5. Back Pressure (psi): Wafer backpressure set point. (-14-+10, less than 0 means vacuum) (Help to improve an uniform polish, negative pressure (vacuum) is used usually)
  6. Ring Force (lbs.): Retaining ring (ViPRR) set point. (0-10) Table Temp: We don't use it
  7. Slurry 1 (ml/mim): Slurry pump 1 flow set point (0-500) (Usually < l00ml/min)
  8. Slurry 2 (ml/mim): Slurry pump 1 flow set point (0-500) (Usually < l00ml/mim)
  9. Rinse (on/off): Turn the DI water rinse on or off during the polish cycle
4. Condition Zone
  1. In-situ conditioning: for long time polishing (outer: 1, inner: 6 for 1" oscillation of polishing arm)
  2. ex-situ conditioning: for short time polishing. (< few minutes)
5. Wet idle
  1. To flood DI water for pad and carrier
6. Auto
  1. Start Polishing: Touch this button to start the currently download process recipe. (Current step is highlight)
    1. Start Conditioning: Touch this button to start the currently download conditioning recipe.
  2. Stop: Touch this button to stop the currently running auto cycle.
  3. Next Step: Touch this button to advance the current polish step.
7. Calibration:
  1. Down force calibration
    1. Overarm setpoint dead weight: Moving the line of set up value VS actual force either up or down linearly
    2. Overarm setpoint gain: Changing slope of line of set up value VS actual force.
    3. Datasheet for the set up value VS force to get:
  2. Overarm down force display calibration
    1. After the down force calibration, this overarm down force display calibration is done.
    2. To get the same number from the display for the given setting point.
8. How to use BYU calibrating potable indicator
  1. Zeroing
  2. Press CAL
  3. Adjust span
  4. Put the detector to the weight
  5. Check the weight of weight for the calibration
  6. Set the weight to zero with ZERO set button
  7. Put another metal plate then place plate with the sensor on the top.
  8. Place it on the pad and doing the calibration.
  9. *The sensor and indicator are so sensitive. Please treat with a care.
9. Slurry calibration
  1. *Purpose: to check the slurry flow rate.
  2. At manual mode: Turn on slurry (make sure your polishing arm is on top of the pad)
  3. Measure amount of slurry actually dispensed and compare with the set up point.
  4. In set up menu: Change calibration factor to increase the actual slurry dispensing amount or decrease it.
  5. For more slurry, decrease the number
  6. For less slurry, increase the number
10. Wafer carrier cleaning and assembling procedure
  1. Unscrew 8 screws for back plate.
  2. Unscrew 3 lifting posts for mounting ring. (Inspect lifting posts)
  3. Inspect drive post
  4. Unscrew 3 stainless steel screws. (Inspect screws)
  5. Clean all parts.
  6. Check o-ring for the base plate.
  7. Take the Gimball out with hammer. Inspect. If it is scratched, replace it.
  8. To install new Gimball, use white plastic tool to position the Gimball properly. First put Gimball into the Gimball house. Second place plastic
  9. tool. Third, hammer on it to let Gimball be installed firmly.
  10. Reassemble all parts.
  11. Turn the carrier around
  12. Take out the retaining ring
  13. Take out Bladder (inflatable seal - black rubber)
  14. Clean them
  15. For new insert, take out paper cover to expose glue side and align to the bottom plate with two small holes.
  16. Place the retaining ring
  17. Put wafer
  18. Use height measure (Mitutoyo) to properly adjust the retaining ring position.
    1. Set the height measure read to be 0 at the middle
    2. Move to out side of insert and let the height measure probe is on the retaining ring side.
    3. The number should be around 1/3 of the thickness of wafer.
    4. For higher retaining ring for thicker wafer, use retaining shim under the retaining ring.
  19. Put the inflatable seal with retaining ring. (You need to move around to get right position
  20. It is about done! Put something on the table before you turn the thing over to protect new insert.
  21. Put the wafer carrier in the wafer pickup station
  22. In manual operation, move the arm down to the wafer carrier
  23. In setup operation, Turn off the retaining ring
  24. Move up the arm
  25. Put two more clamps to hold the wafer carrier.
  26. Turn on the retaining ring at setup menu.
Manual Operation
1. Manual loading and unloading wafer process
  1. Spindle flush at pad (When you reassembled the wafer carrier)
  2. Blow off at pad
  3. Put sample
  4. Move arm to pick up the sample
  5. Turn on vacuum
  6. Press Rinse/Lift
  7. Move up the overarm
  8. Turn off Rinse/Lift
  9. Move down overarm
  10. Turn off vacuum
  11. Turn on Blow off
  12. Move up overarm
  13. Turn off Blow off
2. The pressure sensor currently doesn't work for reading if a wafer is at the loading area
3. To get the pressure sensor to indicate that a wafer is present:
  1. Press "set" until it shows P1
  2. Set P1 to -.6
  3. Press "set" until it shows P0, now a green light show indicate that a wafer is present
4. To get the pressure sensor to indicate that a wafer is no longer present:
  1. Press "set" until it shows P1
  2. Set P1 to 0
  3. Press "set" until it shows P0, the green light should now shut off
5. The top pressure sensor (indicating the wafer suction) needs to be around 500 when a wafer is present
  1. If it doesn't read a value near that, check to make sure the wafer is properly aligned, otherwise it will drop and/or break
Maintenance Tips
1. Keep table and pad wet after use
2. Make sure to flush slurry tubing with clean water to ensure that no slurry is left in the line after use.
  1. Put container of clean water at slurry line (back right of machine).
  2. Go to manual mode, then hit the button to turn on slurry flow.
  3. This should take 5-10 minutes in manual mode, depending on the flow rate.
  4. Make sure to close slurry bucket after removing it from the line.
Other Information
1. Compressed air pressure should be >l00 psi. For our 4" wafer polishing, our current pressure (80 psi) will be fine.
2. Water pressure from chiller to table should be < l0 psi (normally 7-8 psi)
3. For operation with door open, uncable 1,2 and short 3,4.
4. Tips on how to operate wafer pickup to come.
5. More shutdown information to come as well.
Troubleshooting
1. Machine will not power on when button is pressed:
  1. Ensure that the power switch is in the correct position (white, not green). Sometimes it needs to be turned back and forth a couple of times.
2. Machine arm will not move:
  1. Probably a gas flow issue. Turn on the gas valve on the wall behind the machine (left side).
3. Computer screen gives "comm" errors:
  1. Contact Aaron Hawkins. He has dealt with the issue before.
4. No slurry comes out of line:
  1. Check if line is submerged in bucket of slurry.
  2. Run slurry for a couple of minutes on manual mode until it starts coming out.
5. Troubleshooting for other specific problems soon to come:
  1. Wafer breaks during run
  2. Wafer is dropped during run
  3. Machine arm will not pick up wafer
  4. Other problems to come.
6. If there are any questions beyond what is listed here, please email the contact staff above for more information.

Brigham Young University Electrical & Computer Engineering

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