Specific Process Knowledge/Wafer cleaning

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Clean with:

• RCA - Two step process to remove organics and metals
• 7-up & Piranha - Removes organics and alkali ions
• 5% HF - Removing native oxide
• IMEC - Cleaning before fusion bonding
• Soap Sonic - Cleaning of "dirty" wafers when entering the cleanroom

Comparison of Wafer Cleaning Methods

	RCA	7-up & Piranha	5% HF	IMEC	Soap Sonic
Generel description	Two step process to remove organics and metals	Removes organics and alkali ions	Removing native oxide	Cleaning before wafer bonding	Removing dust and particles
Purpose	Mandatory prior furnace processes	When needed and always after KOH etch and Nitride etch in Phosphoric acid	Optional with RCA cleaning	Cleaning before wafer bonding	Cleaning very dirty items that enters the cleanroom. Should be followed by a piranha clean.
Substrate size	#1-25 2", 4" and 6" wafers	#1-25 2", 4" and 6" wafers	#1-25 2", 4" and 6" wafers	#1-25 2" and 4" wafers	All sizes that can go into the bath
Allowed materials	Silicon Poly Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Quartz/fused silica	Silicon Poly Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Quartz/fused silica Pyrex and wafers with Cr ONLY in Mask cleaning bath or beaker	Silicon Poly Silicon Silicon Oxide Silicon Nitride Silicon Oxy-nitride Quartz/fused silica Resists (depending on bath) Pyrex (depending on bath)	Silicon Poly Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Quartz/fused silica Pyrex	All materials