Specific Process Knowledge/Etch/Etching of Polymer: Difference between revisions

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= Polymer dry etching =
'''Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.'''
Upgrading the silicon etch capability at Danchip with the DRIE-Pegasus has pushed our old ASE (Advanced Silicon Etcher) out of the line so that it now only serves as backup silicon dry etcher. We have therefore decided that the ASE must be converted to a polymer etcher instead. Hence, it will join the plasma asher and to some extend the RIE's where polymer etching is allowed. In RIE1 it is only for removing photo resist before or after a RIE etch if the plasma asher cannot be used for some reason. On RIE2 you can get allowance for some other polymer etching but you have to ask first.


*[[Specific Process Knowledge/Etch/Etching of Polymer/Etch of Photo Resist using RIE|Etch of Photo Resist using RIE]]
'''All links to Kemibrug (SDS) and Labmanager Including APV and QC requires login.'''


== Etching of polymers on the ASE ==
'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Etch/Etching_of_Polymer click here]'''
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<!--Page reviewed by jmli 9/8-2022  -->


SPTS has provided some recipes for polymer etching on the ASE. They have NOT been tested yet (As of August 2011) and we are therefore very interested in learning whatever experiences you have. Please contact Jonas. The recipes are located in the root folder. Please copy them to your own folder and modify them there for your own purposes as you would with any other recipe.
<br clear="all" />


{| border="2" cellpadding="2" cellspacing="1"  
== Etching of Polymer ==
|+ '''The polymer recipes'''
 
Stripping of polymer is often done by wet chemistry in a solvent that dissolves the given polymer. If wet chemistry cannot be used or a more controlled etch of the polymer is needed a plasma system is used instead. Plasma ashers are designed for removing polymers in primarily oxygen plasmas. It you need a more directional etch with a masking material RIE2 or ASE can be used.
 
*[[/Polymer Etch by ASE|Polymer Etch by ASE]]
<!-- Link to the process info page in LabAdviser -->
 
*[[Specific Process Knowledge/Lithography/Strip#Plasma_Asher_1|Plasma asher 1]]
<!-- Link to the process info page in LabAvdiser -->
 
*[[Specific Process Knowledge/Lithography/Strip#Plasma_Asher_2|Plasma asher 2]]
 
 
 
 
<br clear="all" />
 
==Comparison of methods for polymer etching==
 
{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"  
|-
|-
! rowspan="2" align="center"| Name
 
! colspan="2" align="center"| Materials
! colspan="8" align="center"| Process parameters
! rowspan="2" align="center" width="300" | Comments by Kevin Riddell SPTS prior to any tests at Danchip
|-
|-
| Mask
|-style="background:silver; color:black"
| Etched
!
| O<sub>2</sub>
![[Specific Process Knowledge/Etch/ASE (Advanced Silicon Etch)|ASE]]
| CO<sub>2</sub>
![[Specific Process Knowledge/Lithography/Strip#Plasma_Asher_1|Plasma asher 1]]
| SF<sub>6</sub>
![[Specific Process Knowledge/Lithography/Strip#Plasma_Asher_2|Plasma asher 2]]
| He/Ar
!Wet Polymer stripping
| Pressure
| Temp
| Coil
| Platen
|-
|-
! poly1
 
| Oxide hard mask
| polyimide/PMMA
| 0
| 50
| 0
| 0
| 4
| 0
| 600
| 150
| This will etch PMGI, PI, & standard resists.  We've never tried it for PMMA, but it should work
|-
|-
! poly2
|-style="background:WhiteSmoke; color:black"
|
!General description
| standard resists, PI PMMA
|The ASE was originally a dedicated deep Si etcher, but with the arrival of the Pegasus it has now been opened for polymer etching.
| 20
|The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers. 
| 0
|The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers. This plasma asher is for Si wafers without metals.
| 0
|Wet polymer etching is used for stripping a resist/polymer when it is no longer needed. E.g. removing resist masks.
| 20
| 3
| 10
| 600
| 150
| This will give higher etch rates &  better selectivities, but slightly more bowed profiles
|-
|-
! poly3
 
|  
|-
| BCB
|-style="background:LightGrey; color:black"
| 43
!Etch direction
| 0
|
| 7
Process dependent: <br>
| 0
Isotropic to anisotropic (vertical to sample surface)
| 4
|
| 20
Isotropic
| 800
|
| 150
Isotropic
| A good start point for PDMS / Ormocer-type Si/ inorganic-containing polymers.  The SF<sub>6</sub>/O<sub>2</sub> ratio will depend on the composition of the polymer.
|
Dissolves the polymer
|-
 
|-
|-
|}
|-style="background:WhiteSmoke; color:black"
!Possible etch reactants
|
*Oxygen plasma
*Oxygen plasma mixed with
**SF<sub>6</sub>
**CF<sub>4</sub>
**Ar
|
*Oxygen plasma
*Oxygen plasma mixed with
**N<sub>2</sub>
**CF<sub>4</sub>
|
*Oxygen plasma
*Oxygen plasma mixed with
**N<sub>2</sub>
|
*The different solvents available at Nanolab, such as
**Acetone
**1165 Remover


|-


=== CYTOP etching: Results by Fei Wang, DTU Nanotech ===


{| border="2" cellpadding="2" cellspacing="1"
|+ '''Recipe'''
|-
|-
! rowspan="2" align="center"| Folder\name
|-style="background:LightGrey; color:black"
! colspan="2" align="center"| Materials
!Substrate size
! colspan="8" align="center"| Process parameters
|
! rowspan="2" align="center" width="300" | Comments
*Samples smaller than 100 mm wafers must be glued to a 100 mm wafer or placed in a reces on a 100 mm wafer.
*<nowiki>#</nowiki>1 100 mm wafer
*<nowiki>#</nowiki>1 150 mm wafer (only when system is set up for 150 mm wafers)
|
*Several small samples
*<nowiki>#</nowiki>25 50 mm wafers
*<nowiki>#</nowiki>25 100 mm wafers
*<nowiki>#</nowiki>25 150 mm wafer
|
*Several small samples
*<nowiki>#</nowiki>25 50 mm wafers
*<nowiki>#</nowiki>25 100 mm wafers
*<nowiki>#</nowiki>25 150 mm wafers
|
*Any sample # and size that can go into the beaker used.
|-
|-
| Mask
 
| Etched
| O<sub>2</sub>
| CO<sub>2</sub>
| SF<sub>6</sub>
| He/Ar
| Pressure
| Temp
| Coil
| Platen
|-
|-
| set\microrea\feicy3
|-style="background:WhiteSmoke; color:black"
| 1.5 µm PR
!'''Allowed materials'''
| CYTOP
|
| 5
Silicon wafers with layers of
| 0
*Silicon oxide or silicon (oxy)nitride
| 0
*Photoresist/e-beam resist
| 20
*PolySilicon
| 3
*Aluminium
| 0
*Polymers (list?)
| 600
*Quartz/fused silica wafers
| 150
*Metals (no Pb and Te) max 5% wafer coverage
| Estimated etch rate ~1.3um/min, selectivity around 1:8, etch load app. 10%
 
Polymer wafers?
|
*Si, SiO2, Si3N4
*Glass
*Metals (no Pb or Te)
*Resists, polymers
|
*Si, SiO2, Si3N4
*Glass
*Resists, polymers
|
*Any material that may go into the beaker used.
|-
|-
|}
|}


 
<br clear="all" />
<gallery caption="The results of the CYTOP etching" widths="250" heights="200" perrow="3">
image:ASEpolymerEtching-cytop1.jpg| Profile
image:ASEpolymerEtching-cytop2.jpg| Top view
image:ASEpolymerEtching-cytop3.jpg| Profile
</gallery>

Latest revision as of 16:48, 6 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


Etching of Polymer

Stripping of polymer is often done by wet chemistry in a solvent that dissolves the given polymer. If wet chemistry cannot be used or a more controlled etch of the polymer is needed a plasma system is used instead. Plasma ashers are designed for removing polymers in primarily oxygen plasmas. It you need a more directional etch with a masking material RIE2 or ASE can be used.




Comparison of methods for polymer etching

ASE Plasma asher 1 Plasma asher 2 Wet Polymer stripping
General description The ASE was originally a dedicated deep Si etcher, but with the arrival of the Pegasus it has now been opened for polymer etching. The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers. The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers. This plasma asher is for Si wafers without metals. Wet polymer etching is used for stripping a resist/polymer when it is no longer needed. E.g. removing resist masks.
Etch direction

Process dependent:
Isotropic to anisotropic (vertical to sample surface)

Isotropic

Isotropic

Dissolves the polymer

Possible etch reactants
  • Oxygen plasma
  • Oxygen plasma mixed with
    • SF6
    • CF4
    • Ar
  • Oxygen plasma
  • Oxygen plasma mixed with
    • N2
    • CF4
  • Oxygen plasma
  • Oxygen plasma mixed with
    • N2
  • The different solvents available at Nanolab, such as
    • Acetone
    • 1165 Remover
Substrate size
  • Samples smaller than 100 mm wafers must be glued to a 100 mm wafer or placed in a reces on a 100 mm wafer.
  • #1 100 mm wafer
  • #1 150 mm wafer (only when system is set up for 150 mm wafers)
  • Several small samples
  • #25 50 mm wafers
  • #25 100 mm wafers
  • #25 150 mm wafer
  • Several small samples
  • #25 50 mm wafers
  • #25 100 mm wafers
  • #25 150 mm wafers
  • Any sample # and size that can go into the beaker used.
Allowed materials

Silicon wafers with layers of

  • Silicon oxide or silicon (oxy)nitride
  • Photoresist/e-beam resist
  • PolySilicon
  • Aluminium
  • Polymers (list?)
  • Quartz/fused silica wafers
  • Metals (no Pb and Te) max 5% wafer coverage

Polymer wafers?

  • Si, SiO2, Si3N4
  • Glass
  • Metals (no Pb or Te)
  • Resists, polymers
  • Si, SiO2, Si3N4
  • Glass
  • Resists, polymers
  • Any material that may go into the beaker used.


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