Specific Process Knowledge/Wafer cleaning/IMEC
IMEC process for cleaning of wafers before fusion bonding:
Based on the IMEC clean process: M. Meuris et al. "The IMEC clean: A new concept for particle and metal removal on Si surfaces.", Solid state Technology, Vol. 38, Issue 7, pp 109-113, 1995.
Has been modified by Karen Birkelund @DTU Nanotek.
| Step | Process | Details | Comments | Comments |
|---|---|---|---|---|
| 1 | Pre-bond cleaning of Si wafers prior to fusion 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, 7-up bath for wafers) and make your own or make in dedicated glass.
Pour up H2SO4 first, put wafers in carrier (USE this in steps 2-7), add H2O2, wait 30 sec, dip wafers. |
Maybe clean the tank the day before! |
| 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, tank for buffer with wetting solution) and make your own. Mix in dedicated bottle (IMEC) in fume hood and add to tank using BHF pump from RCA fumehood! |
. |
| 5 | Rinse | 2 min. rinse | Put into dedicated wet box for IMEC | . |
| 6 | Piranha | Not nitride wafers!
Mixture: H2SO4:H2O2 (4:1) Temp: 80 oC Time: 20 min |
Re-use previous piranha
Makes wafers hydrophilic |
. |
| 7 | Rinse & spin dry | 5 min rinse | . | . |
| 8 | Put wafers in new clean carrier box | . | . | . |