Specific Process Knowledge/Wafer cleaning/7-up & Piranha: Difference between revisions
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Always use one of these after KOH etch or hot phosphoric acid etch to remove alkali ions before further processing. 7-up and Piranha are also used as cleaning solutions '''after''' stripping resist. | Always use one of these after KOH etch or hot phosphoric acid etch to remove alkali ions before further processing. 7-up and Piranha are also used as cleaning solutions '''after''' stripping resist. | ||
[[Image:7-up_6inch.jpg|300x300px|right|thumb|7-up 6" in cleanroom D3. <br\> -Up to 25 wafers of 4" or 6" at a time.<br\> -Materials allowed: Silicon, Silicon | [[Image:7-up_6inch.jpg|300x300px|right|thumb|7-up 6" in cleanroom D3. <br\> -Up to 25 wafers of 4" or 6" at a time.<br\> -Materials allowed: Silicon, Poly Silicon, Silicon Oxide, Silicon Nitride, Silicon Oxynitride,Quartz/fused silica]] | ||
[[Image:7-up_Mask.jpg|300x300px|right|thumb|7-up for masks and glass wafers positioned in cleanroom D3:<br\> -Up to 25 glass wafers of 4" at a time or 4 masks.<br\> -Materials allowed: Silicon, Silicon | [[Image:7-up_Mask.jpg|300x300px|right|thumb|7-up for masks and glass wafers positioned in cleanroom D3:<br\> -Up to 25 glass wafers of 4" at a time or 4 masks.<br\> -Materials allowed: Silicon, Poly Silicon, Silicon Oxide, Silicon Nitride, Silicon Oxynitride, Quartz/fused silica, glass (Pyrex and Soda Lime), chromium]] | ||
<!-- [[Image:7-up_RR3.jpg|300x300px|right|thumb|7-up 4": positioned in cleanroom C1<br\> -Up to 19 wafers of 4" at a time.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi]]--> | <!-- [[Image:7-up_RR3.jpg|300x300px|right|thumb|7-up 4": positioned in cleanroom C1<br\> -Up to 19 wafers of 4" at a time.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi]]--> | ||
Revision as of 11:19, 3 March 2014
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Cleaning of wafers or masks
Cleaning of wafers or masks with sulphuric acid can be done either in a dedicated tank "7-up" or in the fume hood in a beaker "Piranha". Both 7-up and Piranha removes heavy organics. Always use one of these after KOH etch or hot phosphoric acid etch to remove alkali ions before further processing. 7-up and Piranha are also used as cleaning solutions after stripping resist.
The user manual, user APV and contact information can be found in LabManager:
Comparing data for "7-up" and Piranha
| 7-up wafers | 7-up Masks | Piranha | |
|---|---|---|---|
| General description |
Cleaning of wafers using the dedicated tank in cleanroom D3. |
Cleaning of masks using the dedicated tank in cleanroom D3. |
Cleaning of wafers using a beaker in the fumehood in cleanroom B1. Used for glass wafers or wafers with metal or other materials that you are not allowed to put in the 7-up for wafers or masks. |
| Chemical solution | 98% Sulfuric acid and Ammonium sulfate | 98% Sulfuric acid and Ammonium sulfate | 98% Sulfuric acid and Hydrogen peroxide 4:1 add H2O2 to H2SO4 |
| Process temperature | 80 oC | 80 oC | ~70 oC the chemicals will heat up to working temperature during mixing, therefore be careful!First ad H2SO4 then H2O2 |
| Process time | 10 min. | 10 min. | 10 min. |
| Allowed materials |
|
|
All materials (in beaker). |
| Batch size |
1-25 4" or 6" wafers |
1-25 4" or 6" wafers or 1-4 5" masks |
1-5 4" wafer at a time |
| Size of substrate |
4-6" wafers |
4-6" wafers or 5" masks |
All sizes that can fit into the beaker in a dedicated holder |