Specific Process Knowledge/Etch/Etching of Gold

Etching of Gold

Etching of Gold is done wet at Danchip. We have two different solutions:

1. KI:I$_{2}$:H$_{2}$O - 400g:100g:400ml?
2. HNO$_{3}$:HCl - 1:3

Comparing the two solutions

	Iodine based gold etch	Aqua Regia (Kongevand)
General description	Etch of pure aluminium	Etch of aluminium + 1.5% Si
Chemical solution	H$_{2}$O:H$_{3}$PO$_{4}$ 1:2	PES 77-19-04
Process temperature	50 oC	20 oC
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