Specific Process Knowledge/Wafer cleaning/7-up & Piranha
Cleaning of wafers or masks
Cleaning of wafers or masks with sulphuric acid can be done either in a dedicated tank "7-up" or in the fumehood in a beaker "Piranha":
| 7-up | Piranha | |
|---|---|---|
| General description |
Cleaning of wafers or masks using the dedicated tank. |
Cleaning of wafers or masks using a beaker in the fumehood. |
| Chemical solution | 98% Sulfuricacid and Hydrogenperoxide 4:1 | HCl:HNO (3:1) |
| Process temperature | 80 oC | ~70 oC |
| Possible masking materials |
Photoresist (1.5 µm AZ5214E) |
Unmasked - used as a stripper |
| Etch rate |
~100 nm/min |
~(??) nm/min - fast etch |
| Batch size |
1-5 4" wafers at a time |
1-5 4" wafer at a time |
| Size of substrate |
2-6" wafers |
2-6" wafers |