Specific Process Knowledge/Etch/Etching of Chromium

Etching of Chromium

Etching of chromium is done wet at Danchip. We have two solution for this:

1. HNO$_{3}$:H$_{2}$O:cerisulphate - 90ml:1200ml:15g
2. Commercial chromium etch

Etch rate 400-1000 Å/min (depending on the level of oxidation of the metal)

	Chromium etch 1	Chromium etch 2
General description	Etch of chromium	Etch of chronium
Chemical solution	HNO$_{3}$:H$_{2}$O:cerisulphate - 90ml:1200ml:15g	Commercial chromium etch
Process temperature	Room temperature	Room temperature
Possible masking materials:	Photoresist (1.5 µm AZ5214E)	Photoresist (1.5 µm AZ5214E)
Etch rate	~100 nm/min (Pure Al)	~60(??) nm/min
Batch size	1-25 wafers at a time	1-25 wafer at a time
Size of substrate	4" wafers	4" wafers
Allowed materials	Aluminium Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resist	Aluminium Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resist