Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Silicon Nitride Etch using AOE

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Silicon nitride etch with STS recommended silicon nitride recipe

Parameter Recipe name: SiN_res (SiN etch with resist mask)
Coil Power [W] 1300
Platen Power [W] 350
Platen temperature [oC] 0
He flow [sccm] 174
CF4 flow [sccm] 40
Pressure [mTorr] 4
Typical results Test Results
Etch of Si3N4 with DUV mask See images here
Etch rate of Si3N4 ~435nm/min (50% etch load) Marts 2016 by bghe@nanolab
Etch rate of Silicon ~264nm/min (50% etch load) Marts 2016 by bghe@nanolab
Etch rate of DUV resist] ~600nm/min (50% etch load) Marts 2016 by bghe@nanolab


Profile [o] close to 90 degrees see the images


Small variation of the Silicon nitride etch of the STS recommended silicon nitride recipe - with Cr mask

Done by Anders Simonsen @nbi.dk

Parameter Recipe name: SiN_res (SiN etch with resist mask)
Coil Power [W] 1300
Platen Power [W] 350
Platen temperature [oC] 5
He flow [sccm] 174
CF4 flow [sccm] 40
O2 flow [sccm] 4
Pressure [mTorr] 4
Typical results Test Results
Etch of Si3N4 with Cr mask See results here:
Etch rate of Si3N4 ~420nm/min Summer 2022 by asimonsen@nbi.ku
Etch rate of Cr 1:17, see discussion in the summery
Profile [o] close to 90 degrees see the images


Silicon nitride etch with the standard silicon oxide etch

The standard recipe for oxide etching with photo resist as masking material is called: SiO2_res. It can also be used for nitride etching. The parameters and results so fare are as follows:


Parameter Recipe name: SiO2_res (SiO2 etch with resist mask)
Coil Power [W] 1300
Platen Power [W] 200
Platen temperature [oC] 0
He flow [sccm] 174
C4F8 flow [sccm] 5
H2 flow [sccm] 4
Pressure [mTorr] 4


Typical results Test Results
Etch rate of Silicon rich nitride from furnace B2 136nm was etched in 1min (whole wafer) - etched in October 2015 by bghe@nanolab
Etch of Si3N4 with DUV mask See images here


Etch rate of thermal oxide ~230nm/min (5% etch load)
Selectivity SiO2 to AZ resist [:1] ~3
Selectivity SiO2 to DUV resist [:1] ~2.0 - tested May 2013 by Christian Østergaard @nanotech.
Profile [o] ~90


Silicon nitride etch with lower etch rate

Test of etch in silicon nitride (LPCVD). 105nm nitride had to be removed - it was removed after 1min and 40s with a very small over etch in Si.

Parameter Recipe name: Nitr_res (Silicon Nitride etch using resist mask)
Coil Power [W] 700
Platen Power [W] 100
Platen temperature [oC] 0
CF flow [sccm] 5
He flow [sccm] 174
H flow [sccm] 4
Pressure [mTorr] 4


Typical results Resist mask Resist mask
Silicon nitride (LPCVD) etch rate ~60 nm/min 99-108 nm/min (LN/BGHE 20130514)
Selectivity to photo resist [:1] ? ~between 2.5 and 4.0 (LN/BGHE 20130512)
Etch rate in Si ? ?
Etch rate in SiO2 ? ?
Profile [o] not tested not tested
Etch uniforminty over a wafer [o] not tested ± 1.1% to ±1.8% (Eric Jensen @nanotech, oct. 2013)
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