Specific Process Knowledge/Etch/Etching of Silicon Nitride

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Comparing silicon nitride etch methods at Danchip

There are a broad varity of silicon nitride etch methods at Danchip. The methodes are compared here to make it easier for you to compare and choose the one that suits your needs.

• Wet Silicon Nitride Etch
• Etch of Silicon Nitride using RIE
• Etch of Silicon Nitride using AOE
• IBE/Ion Beam Etching using IBSD Ionfab 300

Compare the methods for Silicon Nitride etching

	Wet Silicon Nitride Etch	BHF	RIE (Reactive Ion Etch)	AOE (Advanced Oxide Etch)	IBE/IBSD Ionfab 300
Generel description	Isotropic etch Well suited for removing all nitride on a wafer surface (nitride strip) without a mask. High selectivity Si3N4/Si (>100) and Si3N4/SiO2 (>20) @ 180 C.	Isotropic etch Well suited for removing all PECVD nitride on a wafer surface (nitride strip) without a mask. Etches LPCVD nitride very slowly	Anisotropic etch: vertical sidewalls	Anisotropic etch: vertical sidewalls Deep etch	Primarily for pure physical etch by sputtering with Ar-ions
Possible masking materials	Silicon Oxide PolySilicon	Photoresist PolySilicon Blue film	Photoresist DUV resist E-beam resist Silicon Oxide Silicon Nitride Aluminium Metals if they cover less than 5% of the wafer area (ONLY RIE2!)	Photoresist DUV resist E-beam resist Silicon Oxide Silicon Nitride Aluminium Chromium (please try to avoid it)	Any material that is accepted in the machine
Etch rate range	Si3N4 @ 180 oC: ~84 Å/min Si3N4 @ 160 oC: ~60 Å/min	PECVD nitride: ~400-1000 Å/min	Typically 40-50 nm/min can be increased or decreased by using other recipe parameters.	Process dependent. Tested once to ~60nm/min	Process dependent. Has not been tested yet.
Substrate size	#1-25 100 mm wafers	#1-25 100mm wafers in our 100mm bath	As many small samples as can be fitted on the 100mm carrier. #1 100mm wafer (or smaller with carrier) #1 150mm wafer (only when the system is set up for 150mm)	As many small samples as can be fitted on a 100mm wafer #1 50 mm wafer fitted on a 100mm wafer #1 100 mm wafer #1 150 mm wafers (only RIE2 when set up to 150mm)	As many samples as can be securely fitted on a up to 200mm wafer #1 50 mm wafer with special carrier #1 100 mm wafer with special carrier #1 150 mm wafers with special carrier #1 200 mm wafer
Allowed materials	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist Blue film	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resists DUV resists Other metals if they cover less than 5% of the wafer area (ONLY RIE2!) Quartz/fused silica	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resists DUV resists Aluminium Chromium (try to avoid it) Quartz/fused silica	Silicon Silicon oxides Silicon (oxy)nitrides Metals from the +list Metals from the -list Alloys from the above list Stainless steel Glass III-V materials Resists Polymers Capton tape