Specific Process Knowledge/Etch/Wet Chromium Etch
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All measurements on this page has been made by Nanolab staff.
Wet etching of Chromium
We use the following solution to etch chromium:
- Commercial chromium etch (Chrome Etch 18). You can see the KBA (needs login to kemibrug) 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.
Etch in Fume hood Wet etching of chromium in fume hood at DTU Nanolab is done making your own set up in a beaker in a fume hood - preferably fume hood 6 for Si etch 3 in D-3
You can see the APV here.
PECVD SiO2 and LPCVD SiN coated wafers have been immersed in Cr etch 18 for 10min. Thickness wise: absolutely no changes (roughness after etch not measured)
Normally the etch is reused (if you etch Molybdenum never reuse), but if you need to dispose it, collect it in a bottle marked X waste.
Etching of Chromium in Acid 1 wetbench 11
Always make an agreement with Wetchemistry group before training
The bath is for 6" and 8" wafers.
You can see the APV here.
Overview of the chromium etch process
| Chromium etch in Fume hood | Chromium etch Acid 1 wetbench 11 | |
|---|---|---|
| General description |
Etch of chromium |
Etch of Chromium 6" and 8" wafers |
| Link to safety APV and KBA | see fumehood APV/manual here. | see Wetbench 11 APV/manual here. |
| Chemical solution | Chrome Etch 18 | Chrome Etch 18 |
| Process temperature | Room temperature | Room temperature |
| Possible masking materials | Photoresist (1.5 µm AZ5214E) | Photoresist (1.5 µm AZ5214E) |
| Etch rate | ~ 150 nm/min at 22°C | ~ 150 nm/min at 22°C |
| Batch size | 1-7 4" wafers at a time | Up to 5 6" or 8" wafers at a time |
| Size of substrate | Any size and number that can go inside the beaker in use | 6" and 8" |
| Allowed materials | No restrictions.
Make a note on the beaker of which materials have been processed. |
See the Cross Contamination Sheet for Acid 1 |