View source for Logitech WBS7 - Procedure for Wax Mounting with bulk Crystalbond Stick

 ''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 [[Wafer Bonder (Logitech WBS7)|'''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.<u>2-3mm thick</u>.
**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 <u>2-inch diameter</u> 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 <u>top and bottom</u> 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 [[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).