Specific Process Knowledge/Wafer cleaning/7-up & Piranha: Difference between revisions
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'''Feedback to this page''': '''[mailto:labadviser@ | '''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.danchip.dtu.dk/index.php/Specific_Process_Knowledge/Wafer_cleaning/7-up click here]''' | ||
'''Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.''' | '''Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.''' | ||
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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 contaminants and to a certain 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 contaminants and to a certain 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 should only be used '''AFTER''' stripping resist by other means (see [http://labadviser. | 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 should only be used '''AFTER''' stripping resist by other means (see [http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Strip Resist strip] page). 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!''' | ||
User manuals, risk assessments and contact information can be found on the equipment Info-pages in LabManager:<br> | User manuals, risk assessments and contact information can be found on the equipment Info-pages in LabManager:<br> | ||
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=383 Wafer Cleaning Info page in LabManager] | *[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=383 Wafer Cleaning Info page in LabManager] | ||
*[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=382 Mask Cleaning Info page in LabManager] | |||
*[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=368 Fume hood 01 Info page in LabManager] | |||
*[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=369 Fume hood 02 Info page in LabManager] | |||
*[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=508 Fume Hood 12 (Standard clean) Info page in LabManager] | |||
<gallery widths=200px heights=200px> | |||
WaferClean.jpg|Wafer clean' bath in cleanroom D3 | |||
MaskClean.jpg|Mask clean' bath in cleanroom D3 | |||
FH01-02.jpg|Fume hood 01 and 02 in cleanroom D3 | |||
FH12.JPG|Fume Hood 12 (Standard clean) in cleanroom B1 | |||
</gallery> | |||
===Comparing Wafer/Mask Cleaning baths and Piranha clean=== | ===Comparing Wafer/Mask Cleaning baths and Piranha clean=== | ||
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Cleaning of masks using the dedicated bath in Wet bench 03. | Cleaning of masks using the dedicated bath in Wet bench 03. | ||
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Cleaning of wafers using a beaker in a fumehood in cleanroom | Cleaning of wafers using a beaker in a fumehood in cleanroom D3. Used for glass wafers or wafers with metal or other materials that you are not allowed to put in the Wafer or Mask Cleaning bath. | ||
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{{fnb|1}} In preparing a solution involving an acid, always add the acid last. The exception to this rule is Piranha, in which case you add H<sub>2</sub>O<sub>2</sub>, which is a very strong oxidant, to H<sub>2</sub>SO<sub>4</sub>, which is a very strong acid. This is done because it is potentially explosive and at the very least will cause the solution to become very warm. | <br clear="all"/> | ||
{{fnb|1}} '''In preparing a solution involving an acid, always add the acid last. The exception to this rule is Piranha, in which case you add H<sub>2</sub>O<sub>2</sub>, which is a very strong oxidant, to H<sub>2</sub>SO<sub>4</sub>, which is a very strong acid. This is done because it is potentially explosive and at the very least will cause the solution to become very warm.''' | |||