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 "Piranda":

	7-up	Piranha
General description	Etch of pure Gold with or without photoresist mask.	Etch of pure Gold (as stripper).
Chemical solution	KJ:J$_{2}$:H$_{2}$O (100g:25g:500ml)	HCl:HNO$_{3}$ (3:1)
Process temperature	20 oC	20 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