Specific Process Knowledge/Wafer cleaning/IMEC

Ikke godkendt

IMEC process for cleaning of wafers before fusion bonding:

Step	Process	Details	Comments	Comments
1	Pre bonding cleaning of Si wafers with cavities and SOI wafers with nitride		Use wafers with cavities on and SOI wafers Takes 1½ hours Orient flat to minimize handling Preferable done just before bonding!	Get CLEAN box for wafers!!!
2	Piranha	Mixture: H2SO4:H2O2 (4:1) Temp: 80 oC Time: 5 min (a yellow and a black spot)	Clean tank (cleanroom 4) and make your own or make in dedicated glass. Pour up H2SO4 first, put wafers in carrier (USE this in steps4.1-4.6), add H2O2, wait 30 sec, dip wafers.	Maybe clean the tank the day before! Put into dedicated wet box for IMEC
3	Rinse	2 min. rinse		Put into dedicated wet box for IMEC
4	IMEC	DI water:5% HF:isopropanol (100:10:1) Temp: 25 oC Time: 100 sec (two black spots)	Clean tank (cleanroom 4) and make your own, it needs 2 bottles Bottles are in service room 2 on the left, pump is by Leica microscope in cleanroom 3	Bottle for mixing is in service room 2, use BHF pump from RCA fumehood! Put into dedicated wet box for IMEC
5	Rinse	2 min. rinse
6	Piranha	Not nitride wafers! Mixture: H2SO4:H2O2 (4:1) Temp: 80 oC Time: 20 min	Re-use previous piranha Makes wafers hydrophilic	Put into dedicated wet box for IMEC
7	Rinse & spin dry	5 min rinse		Put into dedicated wet box for IMEC
8	Put wafers in new clean carrier box