Specific Process Knowledge/Etch/Wet Chromium Etch

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Wet etching of Chromium

Fume hood 01 or 02 (for acids and bases) in cleanroom D-3 can be used for wet chromium etching.

Wet etching of chromium at DTU Nanolab is done making your own set up in a beaker in a fume hood - preferably in D-3. You can see the APV here.

We use the following solution to etch chromium:

1. Commercial chromium etch (Chrome Etch 18). You can see the KBA (needs login) here

The etch rate depends on the level of surface oxidation of the chromium metal, but the standard procedure (etch at room temperature: ~22°C) the Etch rate is around 150 nm/min.

Normally the etch is reused, but if you need to dispose it, collect it in a bottle marked O waste.

Overview of the chromium etch process

	Chromium etch 1
General description	Etch of chromium
Link to safety APV and KBA	see fumehood APV/manual here. see Chrome Etch 18 KBA here
Chemical solution	Chrome Etch 18
Process temperature	Room temperature
Possible masking materials	Photoresist (1.5 µm AZ5214E)
Etch rate	~ 150 nm/min at 22°C
Batch size	1-7 4" wafers at a time
Size of substrate	Any size and number that can go inside the beaker in use
Allowed materials	No restrictions. Make a note on the beaker of which materials have been processed.