Specific Process Knowledge/Etch/Etching of Silicon Nitride: Difference between revisions

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Silicon nitride can be etched using either wet chemistry or dry etch equipment. Wet chemistry is mainly used to remove all the nitride on the surface (backside and frontside) of a wafer. Dry etching etches one side at a time and can be used to etch structures with several masking materials.
'''Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.'''


*[[Specific Process Knowledge/Etch/Wet Silicon Nitride Etch|Wet Silicon Nitride Etch]]
'''All links to Kemibrug (SDS) and Labmanager Including APV and QC requires login.'''
*[[/Etch of Silicon Nitride using RIE|Etch of Silicon Nitride using RIE]]
*[[Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)|Etch of Silicon Nitride using AOE]]
*[[Specific Process Knowledge/Etch/IBE/IBSD Ionfab 300|IBE/Ion Beam Etching using IBSD Ionfab 300]]
 
 
==Comparison of wet Silicon Nitride etch and RIE etch for etching of Silicon Nitride==
{| border="2" cellspacing="0" cellpadding="4" align="center"
!
! Wet Silicon Nitride etch
! Buffered HF (BHF)
! RIE
|- valign="top"
! General description
|
*Isotropic etch
*Well suited for removing all nitride on a wafer surface (nitride strip) without a mask. High selectivity Si<sub>3</sub>N<sub>4</sub>/Si (>100) and Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub> (>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
|- valign="top"
!Possible masking materials
|
*Silicon Oxide
*PolySilicon
|
*Photoresist
*PolySilicon
*Blue film
|
*Photoresist
*Silicon Oxide
*Aluminium
*Chromium (ONLY RIE2!)
*Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
|-  valign="top"
!Etch rate
|
*Si<sub>3</sub>N<sub>4</sub> @ 180 <sup>o</sup>C: ~84 Å/min
*Si<sub>3</sub>N<sub>4</sub> @ 160 <sup>o</sup>C: ~60 Å/min
|
*PECVD nitride: ~400-1000 Å/min
|
*Typically 40-50 nm/min can be increased or decreased by using other recipe parameters. 
|- valign="top"
!Batch size
|
*1-25 wafers at a time
|
*1-25 wafers at a time
|
*1 wafer at a time
|- valign="top"
!Size of substrate
|
*4" wafers
|
*4" wafers
|
*4" wafers or smaller pieces
|- valign="top"
!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 resist
*Aluminium
*Chromium (ONLY RIE2!)
*Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
|-
|}
 
 
=This Part is under construction=


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== Comparing silicon etch methodes at Danchip [[Image:section under construction.jpg|70px]]==
== Comparing silicon nitride etch methods at DTU Nanolab ==


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


===Wet etches:===
*[[Specific Process Knowledge/Etch/KOH Etch|KOH Etch]]
*[[Specific Process Knowledge/Etch/Wet Polysilicon Etch|Wet PolySilicon etch]]


===Dry etches:===
*[[Specific Process Knowledge/Etch/Wet Silicon Nitride Etch|Wet Silicon Nitride Etch]]
*[[/Si etch using RIE1 or RIE2|Si etch using RIE1 or RIE2]]
*[[Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Silicon Nitride Etch using AOE|Etch of Silicon Nitride using AOE]]
*[[/Si etch using ASE|Si etch using ASE (Advanced Silicon Etch)]]
*[[Specific Process Knowledge/Etch/IBE&frasl;IBSD Ionfab 300|IBE/Ion Beam Etching using IBSD Ionfab 300]]
*[[Specific Process Knowledge/Etch/DRIE-Pegasus|Si etch using DRIE-Pegasus (Silicon Etch)]]
*[[Specific_Process_Knowledge/Etch/ICP_Metal_Etcher/silicon_nitride|Silicon nitride etch using the ICP metal]]
*[[Specific Process Knowledge/Etch/IBE&frasl;IBSD Ionfab 300/IBE Si etch|Si etch using IBE/IBSD Ionfab 300]]


==Compare the methodes for Si etching==
==Compare the methods for Silicon Nitride etching==


{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"  
{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"  
Line 118: Line 24:
|-style="background:silver; color:black"
|-style="background:silver; color:black"
!
!
![[Specific Process Knowledge/Etch/KOH Etch|KOH Etch]]
![[Specific Process Knowledge/Etch/Wet Silicon Nitride Etch|Wet Silicon Nitride Etch]]
![[Specific Process Knowledge/Etch/Wet Polysilicon Etch|Wet PolySilicon etch]]
![[Specific Process Knowledge/Etch/Wet Silicon Oxide Etch (BHF)|BHF]]
![[Specific Process Knowledge/Etch/RIE (Reactive Ion Etch)|RIE (Reactive Ion Etch)]]
![[Specific Process Knowledge/Etch/ASE_(Advanced_Silicon_Etch)|ASE]]  
![[Specific Process Knowledge/Etch/DRIE-Pegasus|DRIE-Pegasus (Silicon Etch)]]
![[Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)|AOE (Advanced Oxide Etch)]]
![[Specific Process Knowledge/Etch/ASE (Advanced Silicon Etch)|ASE (Advanced Silicon Etch)]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher|ICP Metal Etch]]
![[Specific Process Knowledge/Etch/IBE&frasl;IBSD Ionfab 300|IBE/IBSD Ionfab 300]]
![[Specific Process Knowledge/Etch/IBE&frasl;IBSD Ionfab 300|IBE/IBSD Ionfab 300]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher|ICP Metal]]


|-
|-
Line 132: Line 38:
!Generel description
!Generel description
|
|
*Anisotropic etch in the (100)-plan
*Isotropic etch
*High selectivity to the other plans
*Well suited for removing all nitride on a wafer surface (nitride strip) without a mask. High selectivity Si<sub>3</sub>N<sub>4</sub>/Si (>100) and Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub> (>20) @ 160 C.
*Anisotropic etch: vertical sidewalls independent of the crystal plans
|
|
*Isotropic etch in Silicon and Polysilicon
*Isotropic etch
*Well suited for removing all  PECVD nitride on a wafer surface (nitride strip) without a mask. Etches LPCVD nitride very slowly
|
|
*Can etch isotropic and anisotropic depending on the process parameters
*Anisotropic etch: vertical sidewalls
|
|
*State-of-the-art dry silicon etcher with atmospheric cassette loader
*Anisotropic etch: vertical sidewalls
*Extremely high etch rate and advanced processing options
*Deep etch
|
|
*As RIE but better for high aspect ratio etching and deep etches (higher etch rate)
*Primarily for pure physical etch by sputtering with Ar-ions
*Good selectivity to photoresist
*The ASE is dedicated to polymer etch, which can affect the Si etch stability.
|
|
*This is dedicated to metal etch. So fare only Si etch of nanostructures has been explored on the system.
*Anisotropic etch: vertical sidewalls
|
*Primarily for pure physical etch by sputtering with Ar-ions
|-
|-


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!Possible masking materials
!Possible masking materials
|
|
*Silicon Nitride
*Silicon Oxide
*Silicon Oxide
*PolySilicon
|
|
*Photoresist
*Photoresist
*PolySilicon
*Blue film
|
|
*Photoresist
*Photoresist
*DUV resist
*E-beam resist
*E-beam resist
*Silicon Oxide
*Silicon Oxide
*Silicon Nitride
*Silicon Nitride
*Aluminium
*Aluminium
*Chromium (ONLY RIE2!)
*Metals if they cover less than 5% of the wafer area
*Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
|
*Photoresist and zep resist
*Silicon Oxide
*Silicon Nitride
*Aluminium oxide
|
|
*Photoresist
*Photoresist
*DUV resist
*E-beam resist
*Silicon Oxide
*Silicon Oxide
*Silicon Nitride
*Silicon Nitride
*Aluminium
*Aluminium
*Chromium (please try to avoid it)
|
|
*Photo-, DUV- and e-beamresist
*Any material that is accepted in the machine
*Silicon Oxide
*Silicon Nitride
*Aluminium
*Cr
*Ti
|
|
*Any material that is accepted in the machine
*Resists
*other materials from the allowed list of materials
|-
|-


Line 193: Line 91:
!Etch rate range
!Etch rate range
|
|
*Si(100) @80<sup>o</sup>C: 1.29+0.05 µm/min
*Si<sub>3</sub>N<sub>4</sub> @ 160 <sup>o</sup>C: ~26 Å/min
*Si(100) @70<sup>o</sup>C: ~0.7 µm/min
*Si(100) @60<sup>o</sup>C: ~0.4 µm/min
|
*~100-200 nm/min, highly dependent on doping level
|
|
*<40nm/min to >600nm/min depending on recipe parameters and mask design
*PECVD nitride: ~40.0-100.0 nm/min
*Stoichiometric LPCVD nitride: ~0.65-8 nm/min <!-- Copyrigth issues kabi (''Yannick Seis, KU, 2019'')-->
|
|
*Up to 18-20 µm/min depending on recipe, mask design and aspect ratio.
*Probably betweeb 20-300 nm/min depending on the process parameters
|
|
*<130nm/min to >5.6 µm/min depending on recipe, mask design and aspect ratio.
*Process dependent.
*Tested once to ~60nm/min
|
|
*Process dependant. The nano etch is in the range 59-311 nm/min
*Process dependent.
*Has not been tested yet.
|
|
*Process dependant. Has been tested in the range 17-31 nm/min
*Process dependent
*60-65 nm/min has been tested
|-
|-


Line 214: Line 112:
!Substrate size
!Substrate size
|
|
*<nowiki>#</nowiki>25 wafers of 100mm in our 100mm bath
*<nowiki>#</nowiki>1-25 4" and 6" wafers  
*<nowiki>#</nowiki>1-5 wafers of 100mm or 50mm in "Fumehood KOH"
*<nowiki>#</nowiki>25 wafers of 100mm or 150mm in our 6" bath
|
|
*<nowiki>#</nowiki>25 100 mm wafers in our 100mm bath
*<nowiki>#</nowiki>1-25 4"-6" wafers  
|
|
*As many small samples as can be fitted on the 100mm carrier.
*As many small samples as can be fitted on the 100mm carrier (bad/no cooling!)
*<nowiki>#</nowiki>1 100mm wafer (or smaller with carrier)
*<nowiki>#</nowiki>1 100mm wafer (or smaller with carrier)
*<nowiki>#</nowiki>1 150mm wafer (only when the system is set up for 150mm)  
*<nowiki>#</nowiki>1 150mm wafer (only when the system is set up for 150mm)  
Line 227: Line 123:
*<nowiki>#</nowiki>1 50 mm wafer fitted on a 100mm wafer
*<nowiki>#</nowiki>1 50 mm wafer fitted on a 100mm wafer
*<nowiki>#</nowiki>1 100 mm wafer
*<nowiki>#</nowiki>1 100 mm wafer
*<nowiki>#</nowiki>1 150 mm wafers (only when the system is set up to 150mm)
*<nowiki>#</nowiki>1 150 mm wafers (only RIE2 when set up to 150mm)
|
*As many small samples as can be fitted on a 100mm wafer
*<nowiki>#</nowiki>1 50 mm wafer fitted on a 100mm wafer
*<nowiki>#</nowiki>1 100 mm wafer
*<nowiki>#</nowiki>1 150 mm wafers (only when the system is set up to 150mm)
|
*As many small samples as can be fitted on a 150mm wafer
*<nowiki>#</nowiki>5 50 mm wafer fitted on a 150mm wafer
*<nowiki>#</nowiki>1 100 mm wafer on a 150mm wafer
*<nowiki>#</nowiki>1 150 mm wafers (The system is normally set up to 150mm)  
|
|
*As many samples as can be securely fitted on a up to 200mm wafer
*As many samples as can be securely fitted on a up to 200mm wafer
Line 244: Line 130:
*<nowiki>#</nowiki>1 150 mm wafers with special carrier
*<nowiki>#</nowiki>1 150 mm wafers with special carrier
*<nowiki>#</nowiki>1 200 mm wafer
*<nowiki>#</nowiki>1 200 mm wafer
|
*Set up for 150mm wafers
*Smaller samples can be processes when fixed to a 150mm carrier wafer.
|-
|-
|-style="background:WhiteSmoke; color:black"
|-style="background:WhiteSmoke; color:black"
Line 252: Line 141:
*Silicon Nitride
*Silicon Nitride
*Silicon Oxynitride
*Silicon Oxynitride
*Other materials (only in "Fumehood KOH")
|
|
*Silicon
*Silicon
Line 259: Line 147:
*Silicon Oxynitride
*Silicon Oxynitride
*Photoresist
*Photoresist
*Blue film
|
|
*Silicon
*Silicon
Line 265: Line 154:
*Silicon Oxynitride
*Silicon Oxynitride
*Photoresist
*Photoresist
*E-beam resist
*E-beam resists
*Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
*DUV resists
*Quartz/fused silica
*Other metals if they cover less than 5% of the wafer area
|
*Silicon
*Silicon Oxide
*Silicon Nitride
*Silicon Oxynitride
*Photoresist
*zep resist
*Aluminium oxide
*Quartz/fused silica
*Quartz/fused silica
|
|
Line 283: Line 164:
*Silicon Oxynitride
*Silicon Oxynitride
*Photoresist
*Photoresist
*E-beam resist
*E-beam resists
*DUV resists
*Aluminium
*Aluminium
*Quartz/fused silica
*Chromium (try to avoid it)
|
*Silicon
*Photoresist/e-beam resist
*PolySilicon
*Silicon oxide
*Silicon (oxy)nitride
*Aluminium
*Titanium
*Chromium
*Quartz/fused silica
*Quartz/fused silica
|
|
Line 309: Line 182:
*Polymers
*Polymers
*Capton tape
*Capton tape
|
*Silicon
*Silicon Oxide
*Silicon Nitride
*Silicon Oxynitride
*Photoresist
*E-beam resists
*DUV resists
*Aluminium (Al, Al2O3, AlN)
*Chromium
*Titanium (Ti, TiW, TiN, TiO2)
*Tungsten (W)
*Molybdynem
*Quartz/fused silica
|-
|-
|}
|}


<br clear="all" />
<br clear="all" />

Latest revision as of 11:18, 14 February 2023

Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.

All links to Kemibrug (SDS) and Labmanager Including APV and QC requires login.

Feedback to this page: click here

Comparing silicon nitride etch methods at DTU Nanolab

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


Compare the methods for Silicon Nitride etching

Wet Silicon Nitride Etch BHF ASE AOE (Advanced Oxide Etch) IBE/IBSD Ionfab 300 ICP Metal


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) @ 160 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
  • Anisotropic etch: vertical sidewalls
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
  • 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
  • Resists
  • other materials from the allowed list of materials
Etch rate range
  • Si3N4 @ 160 oC: ~26 Å/min
  • PECVD nitride: ~40.0-100.0 nm/min
  • Stoichiometric LPCVD nitride: ~0.65-8 nm/min
  • Probably betweeb 20-300 nm/min depending on the process parameters
  • Process dependent.
  • Tested once to ~60nm/min
  • Process dependent.
  • Has not been tested yet.
  • Process dependent
  • 60-65 nm/min has been tested
Substrate size
  • #1-25 4" and 6" wafers
  • #1-25 4"-6" wafers
  • As many small samples as can be fitted on the 100mm carrier (bad/no cooling!)
  • #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
  • Set up for 150mm wafers
  • Smaller samples can be processes when fixed to a 150mm carrier 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
  • 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
  • Silicon
  • Silicon Oxide
  • Silicon Nitride
  • Silicon Oxynitride
  • Photoresist
  • E-beam resists
  • DUV resists
  • Aluminium (Al, Al2O3, AlN)
  • Chromium
  • Titanium (Ti, TiW, TiN, TiO2)
  • Tungsten (W)
  • Molybdynem
  • Quartz/fused silica


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