Difference between revisions of "Logitech WBS7 - Procedure for Wax Mounting with bulk Crystalbond Stick"

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(draft recipe)
 
(updated to 150°C, quantity of wax for 4-inch wafers, and place both wafers in contact on hotplate, not on Logitech.)
 
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''Contributed by Miguel Daal, Mazin Group -- 2018-04-24''
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Draft only - in progress. -- Demis 2019-01-28
  
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''Procedure for wax-mounting a 100mm Silicon wafer to another 100mm silicon carrier wafer, using the [[Wafer Bonder (Logitech WBS7)|'''Logitech WBS7 Wafer Bonder''']].''
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* Heat up lower substrate on hotplate at 135°C
  
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* Apply XYZ grams of crystalbond wax, with stick, to the surface. Spread so that enough wax is present so that entire underside of upper substrate will be in contact with wax. Remove from hotplate and cool. If wax got on the underside, can spin face-down on POLOS spinner @ 2000rpm with ACE squirt bottle to remove.
  
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*Cover Hotplate surface with tinfoil, heat hotplate to 150°C.
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* Place carrier wafer on Logitech bonder surface, wax face-up.
  
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**Bay 5 solvent bench is preferred
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* Place sample to be bonded on top
  
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**Keep flammable solvents away!
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* Place 110mm chemical filter paper on top
  
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*Place 4" polished handle wafer on hotplate.
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* Close lid, secure lid clamp
  
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*Apply wax to center of carrier wafer only.
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* Run recipe:
  
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**For mounting a 4-inch wafer, you need a good amount of wax to ensure coverage to wafer edges, eg.<u>2-3mm thick</u>.
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** XYZ °C
  
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**For 4-inch wafers, We have found that ~2.3 grams of wax is the right amount. Cut a ~1cm chunk off the CrystalBond wax stick with razor, then cut that into 2/3rds, weigh with tared scale in Bay 5.
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** XYZ seconds
  
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**Should produce approximately <u>2-inch diameter</u> size puddle of crystal bond wax.
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** Vacuum etc.?
  
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**If you need to adjust the wax amount, you can use a transparent top-substrate to observe whether full coverage is achieved. Few millimeter-sized bubbles typically are acceptable.
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*Place the top wafer on the melted wax at this step, and align wafer flats while wax is wet.
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*Remove wafers from hotplate and cool on ''clean'' napkin (do not let wax stick to surfaces while cooling). Check that wafer flat alignment is good.
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*Open Logitech Bonder chamber:
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**Unscrew clamp until higher than clamp arm,
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**Swing front of clamp arm to the left (Difficult to disengage),
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**Lift bonder lid (also takes some force to open - ignore vacuum reading on digital display)
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*Place 6" filter paper on the glass plate of the logitech.
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*Place wafers on top of the filter paper, on the glass plate of the Logitech bonder.
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*Place 6" filter paper on top of the wafers. Wafers shouldhave filter paper on <u>top and bottom</u> to catch excess wax.
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*Close and lock Logitech bonder hatch.
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*Turn on Logitech bonder power (bottom right of machine chassis)
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*On front panel of  Logitech bonder, confirm that Applied Pressure gauge is set to 5 psi.
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*Enter the process settings:
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**[setup] -> [Temp]
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***Bonding: 120°C
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***Endpoint: 65°C
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***Offset: 20°C
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***Units: C
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**[setup] -> [Vac Thres]
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***Proceed if Below: 2.4E+01 mBar
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***Abort if Below: 3.2E+01 mBar
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**[setup] -> [Process Control]
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***Process: Heat + Outgas
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***Soak: 5min
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***Bond: 15min
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***O.G. Limit: 20min
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***P.P. del: 1min
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**[Setup] -> [Heads]
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***Head 1 On
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*Start Process: [Process] -> [Start]
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*Process takes about 45min
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**Unload when it displays ''Status: Ready''
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**It is normal to see wax on the filter paper, indicating full/over-coverage. However you might need to adjust the wax amount to prevent too much wax escaping the wafer and causing too thick a bonding layer. About ~1cm of leaking wax on the filter paper is ideal.
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*If wax leaked onto the glass plate: remove glass plate and clean with Acetone+Wipe. The surfaces must be very clean of wax when you're done, or else the lid or wafers may get stuck on the next run.
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*Turn off Logitech bonder (bottom right of machine chassis)
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**Close lid and clamp
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*Clean excess wax off your wafer using the [[Wet Benches#Automated Wet-processing Spinners .28POLOS.29|POLOS Spinners]], and an Acetone squirt bottle, followed by ISO & N2 dry (run both sides of the wafer, multiple times if needed).

Latest revision as of 10:52, 26 April 2023

Contributed by Miguel Daal, Mazin Group  -- 2018-04-24

Procedure for wax-mounting a 100mm Silicon wafer to another 100mm silicon carrier wafer, using the Logitech WBS7 Wafer Bonder.

  • Cover Hotplate surface with tinfoil, heat hotplate to 150°C.
    • Bay 5 solvent bench is preferred
    • Keep flammable solvents away!
  • Place 4" polished handle wafer on hotplate.
  • Apply wax to center of carrier wafer only.
    • For mounting a 4-inch wafer, you need a good amount of wax to ensure coverage to wafer edges, eg.2-3mm thick.
    • For 4-inch wafers, We have found that ~2.3 grams of wax is the right amount. Cut a ~1cm chunk off the CrystalBond wax stick with razor, then cut that into 2/3rds, weigh with tared scale in Bay 5.
    • Should produce approximately 2-inch diameter size puddle of crystal bond wax.
    • If you need to adjust the wax amount, you can use a transparent top-substrate to observe whether full coverage is achieved. Few millimeter-sized bubbles typically are acceptable.
  • Place the top wafer on the melted wax at this step, and align wafer flats while wax is wet.
  • Remove wafers from hotplate and cool on clean napkin (do not let wax stick to surfaces while cooling). Check that wafer flat alignment is good.
  • Open Logitech Bonder chamber:
    • Unscrew clamp until higher than clamp arm,
    • Swing front of clamp arm to the left (Difficult to disengage),
    • Lift bonder lid (also takes some force to open - ignore vacuum reading on digital display)
  • Place 6" filter paper on the glass plate of the logitech.
  • Place wafers on top of the filter paper, on the glass plate of the Logitech bonder.
  • Place 6" filter paper on top of the wafers. Wafers shouldhave filter paper on top and bottom to catch excess wax.
  • Close and lock Logitech bonder hatch.
  • Turn on Logitech bonder power (bottom right of machine chassis)
  • On front panel of  Logitech bonder, confirm that Applied Pressure gauge is set to 5 psi.
  • Enter the process settings:
    • [setup] -> [Temp]
      • Bonding: 120°C
      • Endpoint: 65°C
      • Offset: 20°C
      • Units: C
    • [setup] -> [Vac Thres]
      • Proceed if Below: 2.4E+01 mBar
      • Abort if Below: 3.2E+01 mBar
    • [setup] -> [Process Control]
      • Process: Heat + Outgas
      • Soak: 5min
      • Bond: 15min
      • O.G. Limit: 20min
      • P.P. del: 1min
    • [Setup] -> [Heads]
      • Head 1 On
  • Start Process: [Process] -> [Start]
  • Process takes about 45min
    • Unload when it displays Status: Ready
    • It is normal to see wax on the filter paper, indicating full/over-coverage. However you might need to adjust the wax amount to prevent too much wax escaping the wafer and causing too thick a bonding layer. About ~1cm of leaking wax on the filter paper is ideal.
  • If wax leaked onto the glass plate: remove glass plate and clean with Acetone+Wipe. The surfaces must be very clean of wax when you're done, or else the lid or wafers may get stuck on the next run.
  • Turn off Logitech bonder (bottom right of machine chassis)
    • Close lid and clamp
  • Clean excess wax off your wafer using the POLOS Spinners, and an Acetone squirt bottle, followed by ISO & N2 dry (run both sides of the wafer, multiple times if needed).
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