Specific Process Knowledge/Etch/Etching of Gold

Etching of Gold

Etching of Gold is done wet at Danchip making your own set up in a beaker in the fumehood. We have two different solutions:

1. Iodine etch: KI:I$_{2}$:H$_{2}$O - 100g:25g:500ml - standard at Danchip
2. Aqua Regia (Kongevand): HNO$_{3}$:HCl - 1:3

Comparing the two solutions

	Iodine based gold etch	Aqua Regia (Kongevand)
General description	Etch of pure Gold	Etch of pure Gold
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	1-25 wafers at a time	1-25 wafer at a time
Size of substrate	2-6" wafers	2-6" wafers