Specific Process Knowledge/Wafer cleaning: Difference between revisions
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'''Feedback to this page''': '''[mailto:labadviser@ | {{cc-nanolab}} | ||
'''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 click here]''' | |||
== Cleaning of wafers == | == Cleaning of wafers == | ||
__NOTOC__ | |||
During processing it is sometimes mandatory, necessary or just recommended to clean the wafers or the photo lithographic masks. This can be done by different cleaning procedures depending on what the wafers have been exposed to and where they are going to be further processed. | During processing it is sometimes mandatory, necessary or just recommended to clean the wafers or the photo lithographic masks. This can be done by different cleaning procedures depending on what the wafers have been exposed to, and where they are going to be further processed. In the comparison table below is listed different cleaning procedures available at nanolab. | ||
===Wafers that go into the high temperature furnaces=== | |||
As a general rule all wafers that go into the high temperature furnaces need a full RCA clean directly before the furnace step. | As a general rule all wafers that go into the high temperature furnaces need a full RCA clean directly before the furnace step. | ||
There are, however, some exception to this rule. Please find more information on wafer cleaning before furnace processes [https://labadviser.nanolab.dtu.dk/index.php?title=Specific_Process_Knowledge/Thermal_Process/Storage_and_cleaning_of_wafer_to_the_A,_B,_C_and_E_stack_furnaces here]. | |||
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===Wafers that have been in | ===Wafers that have been in KOH baths (Si Etch 1, 2 and 3), KOH BHF baths or 'Nitride etch: H3PO4' (warm phosphoric acid)=== | ||
Wafers that have been etched in KOH | Wafers that have been etched in KOH are often etched in warm phosphoric acid afterwards to strip the silicon nitride etch mask. Therefore, wafers that have been processed in KOH baths, KOH BHF baths or phosphoric acid nitride etch baths often need at minimum a 7-up or Piranha clean before they can be further processed (in order to remove KOH etch residuals and metal ions). | ||
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===Items that have been outside the cleanroom=== | ===Items that have been outside the cleanroom=== | ||
Before bringing samples into the cleanroom you have to get approval from Nanolab ("Bring samples into cleanroom"-procedure). The approval process and cleaning procedure is described on <b>[[Specific_Process_Knowledge/Wafer_cleaning/Bring_samples_into_cleanroom | here]]</b>. Please note that the approval for bringing samples into the cleanroom is personal (and fellow group members need to send in seperate request). | |||
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===Masks=== | ===Masks=== | ||
Masks that have become dirty by dust particles or resist residues have to be cleaned in the 7-up (mask) bath before use. | Masks that have become dirty by dust particles or resist residues have to be cleaned in the 7-up (mask) bath before use. You can find more information [https://labadviser.nanolab.dtu.dk/index.php?title=Specific_Process_Knowledge/Wafer_cleaning/7-up_%26_Piranha here]. | ||
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! | ! | ||
![[Specific Process Knowledge/Wafer cleaning/RCA|RCA]] | ![[Specific Process Knowledge/Wafer cleaning/RCA|RCA]] | ||
![[Specific Process Knowledge/Wafer cleaning/7-up & Piranha| | ![[Specific Process Knowledge/Wafer cleaning/7-up & Piranha|Wafer/Mask Clean baths & Piranha]] | ||
![[Specific Process Knowledge/Wafer cleaning/cleaning with HF|5% HF]] | ![[Specific Process Knowledge/Wafer cleaning/cleaning with HF|5% HF]] | ||
![[Specific Process Knowledge/Wafer cleaning/IMEC|IMEC]] | ![[Specific Process Knowledge/Wafer cleaning/IMEC|IMEC]] | ||
![[Specific Process Knowledge/Wafer cleaning/Cleaning with Soap Sonic|Soap Sonic]] | ![[Specific Process Knowledge/Wafer cleaning/Cleaning with Soap Sonic|Soap Sonic]] | ||
![[Specific Process Knowledge/Wafer cleaning/Post CMP Cleaner|Post CMP Cleaner]] | |||
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|-style="background:WhiteSmoke; color:black" | |-style="background:WhiteSmoke; color:black" | ||
!Generel description | !Generel description | ||
|Two step process to remove organics and metals | |Two step process to remove traces of organics and metals | ||
|Removes organics and alkali ions | |Removes traces of organics and alkali ions | ||
|Removing native oxide | |Removing native oxide | ||
|Removing dust, organics and alkali ions and slightly polish the surface. | |Removing dust, traces of organics and alkali ions and slightly polish the surface. | ||
Make the surface hydrophillic | Make the surface hydrophillic | ||
|Removing dust and particles | |Removing dust and particles | ||
|Removing slurry residues from the CMP | |||
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|Recommended cleaning and treatment before wafer bonding | |Recommended cleaning and treatment before wafer bonding | ||
|Mandatory cleaning of very dirty items that enters the cleanroom. Should always be followed by a piranha clean. | |Mandatory cleaning of very dirty items that enters the cleanroom. Should always be followed by a piranha clean. | ||
|Recommended cleaning after CMP | |||
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*All sizes that can go into the bath | *All sizes that can go into the bath | ||
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*<nowiki>#</nowiki>1 20x20mm sample as well as 2", 4" and 6inch wafers | |||
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*Silicon Oxynitride | *Silicon Oxynitride | ||
*Quartz/fused silica | *Quartz/fused silica | ||
*Pyrex, other glass and Silicon wafers with Cr ONLY allowed in | *Pyrex, other glass and Silicon wafers with Cr ONLY allowed in Mask Cleaning bath or beaker in fumehood | ||
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*Silicon | *Silicon | ||
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*All materials | *All materials | ||
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*Silicon | |||
*Poly Silicon | |||
*Silicon Oxide | |||
*Quartz/fused silica | |||
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