Specific Process Knowledge/Wafer cleaning/7-up & Piranha: Difference between revisions
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Samples not allowed or not compatible with these baths can be cleaned manually in a beaker filled with the so called "Piranha" mixture using one of the acids/bases fume hoods. This mixture consists of concentrated sulfuric acid and hydrogen peroxide forming very aggressive and reactive peroxide species (as in 7-Up) which is very effective at removing organic contaminents and to some extent some metal ions. | Samples not allowed or not compatible with these baths can be cleaned manually in a beaker filled with the so called "Piranha" mixture using one of the acids/bases fume hoods. This mixture consists of concentrated sulfuric acid and hydrogen peroxide forming very aggressive and reactive peroxide species (as in 7-Up) which is very effective at removing organic contaminents and to some extent some metal ions. | ||
Always use one of these cleaning procedures after KOH etch or hot phosphoric acid etch (Nitride etch) to remove alkali ions before further processing. 7-up and Piranha are always used as cleaning solutions '''after''' stripping resist if you have resist on your samples. Cleaning samples with resist coatings or significant amounts of other organic substances can be very dangerous, because 7-Up and Piranha are so aggressive. These solutions are intended for removing TRACES of organic matter. Adding large amounts of organics can lead to explosive reactions! | Always use one of these cleaning procedures after KOH etch or hot phosphoric acid etch (Nitride etch) to remove alkali ions before further processing. 7-up and Piranha are always used as cleaning solutions '''after''' stripping resist if you have resist on your samples. Cleaning samples with resist coatings or significant amounts of other organic substances can be very dangerous, because 7-Up and Piranha are so aggressive. '''These solutions are intended for removing TRACES of organic matter. Adding large amounts of organics can lead to explosive reactions!''' | ||
[[Image:7-up_RR3.jpg|300x300px|right|thumb|Wafer clean bath 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_RR3.jpg|300x300px|right|thumb|Wafer clean bath 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|Mask clean 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_Mask.jpg|300x300px|right|thumb|Mask clean 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| | <!-- [[Image:7-up_RR3.jpg|300x300px|right|thumb|Fume hood 01 and 02 in cleanroom D3<br\> -Up to 19 wafers of 4" at a time.<br\> -Materials allowed: Silicon, Silicon oxide, Silicon nitride, PolySi]]--> | ||
'''The user manual, user APV and contact information can be found in LabManager:''' | '''The user manual, user APV and contact information can be found in LabManager:''' | ||