Difference between revisions of "Logitech WBS7 - Procedure for Wax Mounting with bulk Crystalbond Stick"
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(updated open/close procedure) |
(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 |
+ | ''Contributed by Miguel Daal, Mazin Group -- 2018-04-24'' |
− | Procedure for wax-mounting a 100mm Silicon wafer to another 100mm silicon carrier wafer. |
+ | ''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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+ | *Cover Hotplate surface with tinfoil, heat hotplate to 150°C. |
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+ | **Bay 5 solvent bench is preferred |
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+ | **Keep flammable solvents away! |
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− | ** Then remove from hotplate. and cool. |
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+ | *Apply wax to center of carrier wafer only. |
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− | ** Swing front of clamp arm to the left (Difficult to disengage), |
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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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+ | **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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− | ** Align work wafer on top of handle wafer placed. |
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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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− | ** Align the two wafers' flats. |
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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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+ | **Swing front of clamp arm to the left (Difficult to disengage), |
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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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− | *** Offset: 20°C |
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− | *** Units: C |
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+ | *On front panel of Logitech bonder, confirm that Applied Pressure gauge is set to 5 psi. |
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− | *** Process: Heat + Outgas |
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− | *** |
+ | ***Offset: 20°C |
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+ | ***Units: C |
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− | * |
+ | ***Process: Heat + Outgas |
+ | ***Soak: 5min |
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+ | ***Bond: 15min |
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+ | *Start Process: [Process] -> [Start] |
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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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+ | *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
- [setup] -> [Temp]
- 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).