Specific Process Knowledge/Wafer cleaning/7-up & Piranha: Difference between revisions
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==Cleaning of wafers or masks== | ==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" | 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. | Both 7-up and Piranha removes heavy organics. | ||
Always use one of these after KOH 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 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 4. <br\> -Up to 25 wafers of 4" or 6" at a time.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi]] | |||
[[Image:7-up_Mask.jpg|300x300px|right|thumb|7-up for masks and glass wafers positioned in cleanroom 4:<br\> -Up to 25 glass wafers of 4" at a time or 4 masks.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi, glass, chromium]] | |||
[[Image:7-up_RR3.jpg|300x300px|right|thumb|7-up 4": positioned in cleanroom 3<br\> -Up to 19 wafers of 4" at a time.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi]] | |||
===Comparing data for "7-up" and Piranha=== | ===Comparing data for "7-up" and Piranha=== | ||
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Revision as of 10:11, 28 October 2013
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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 to remove alkali ions before further processing. 7-up and Piranha are also used as cleaning solutions after stripping resist.
Comparing data for "7-up" and Piranha
| "7-up" | Piranha | |
|---|---|---|
| General description |
Cleaning of wafers or masks using the dedicated tanks. There are one tank for masks and glass wafers and one for 4-6" Si wafers in cleanroom 4 and one tank in cleanroom 3 for 4" Si wafers only. |
Cleaning of wafers using a beaker in the fumehood in cleanroom 2. Used for glass wafers or wafers with metal or other materials that you are not allowed to put in the 7-up for wafers. |
| Chemical solution | 98% Sulfuric acid and Ammonium sulfate | 98% Sulfuric acid and Hydrogen peroxide 4:1 add H2O2 to H2SO4 |
| Process temperature | 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. |
| Allowed materials |
Dependent on which bath is used, look at the text in the pictures. |
All materials (in beaker). |
| Batch size |
1-19/25 4" wafers or 4 masks at a time |
1-5 4" wafer at a time |
| Size of substrate |
4-6" wafers |
2-4" wafers |