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

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Ething of Gold can be done either wet or dry. For wet etching please see below on this page. Dry etching can be done with [[Specific Process Knowledge/Etch/IBE/IBSD Ionfab 300|IBE]] by sputtering with Ar ions.  
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==Etching of Gold==
==Etching of Gold==
[[Image:fumehoodetch-gold.jpg |300x300px|thumb|Wet Gold Etch: Done in the fumehood positioned in cleanroom 2]]
Etching of Gold is done wet at Danchip making your own set up in a beaker in the fumehood. We have two different solutions:


# Iodine etch: KI:I<sub>2</sub>:H<sub>2</sub>O - 100g:25g:500ml - standard at Danchip. Can be used with AZ resist as mask.
Etching of Gold can be done either by wet etch, or by sputtering with ions.
# Aqua Regia (Kongevand): HNO<sub>3</msub>:HCl - 1:3 - A very strong acid witch will etch most metals and are therefore used when you wish to remove all the gold from your wafer. '''you have to be very carefull when you work with Aqua Regia (Kongevand) It can generate nitrous gases witch are very toxic!!'''
*[[Specific Process Knowledge/Etch/Wet Gold Etch|Etching of Gold by wet etch]]
*[[Specific_Process_Knowledge/Etch/IBE&frasl;IBSD Ionfab 300/IBE Au etch|Sputtering of Au]]
<br clear="all" />


==Comparison of Gold Etch Methods==


===Comparing the two solutions===
{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"
|-


{| border="2" cellspacing="0" cellpadding="4" align="left"
!
! Iodine based gold etch
! Aqua Regia (Kongevand)
|-
|'''General description'''
|
Etch of pure Gold with or without photoresist mask.
|
Etch of pure Gold (as stripper).
|-
|-
|'''Chemical solution'''
|-style="background:silver; color:black"
|KI:I<sub>2</sub>:H<sub>2</sub>O  (100g:25g:500ml)
!
|HCl:HNO<sub>3</sub>  (3:1)
![[Specific Process Knowledge/Etch/Wet Gold Etch|Au wet etch 1]]
![[Specific Process Knowledge/Etch/Wet Gold Etch|Au wet etch 2]]
![[Specific_Process_Knowledge/Etch/IBE&frasl;IBSD Ionfab 300|IBE (Ionfab300+)]]
|-
|-
|'''Process temperature'''
|20 <sup>o</sup>C


|20 <sup>o</sup>C
|-
|-style="background:WhiteSmoke; color:black"
!Generel description
|Wet etch of Au using iodine based chemistry
|Wet etch of Au using Aqua Regina
|Sputtering of Au - pure physical etch
|-


|-
|-style="background:LightGrey; color:black"
!Etch rate range
|
*~100nm/min
|
*680 nm/min (dilute) or faster (concentrated). Mainly used for complete removal of metals
|
*~55nm/min (acceptance test)
|-
|-


|'''Possible masking materials'''
|-
|-style="background:WhiteSmoke; color:black"
!Etch profile
|
|
Photoresist (1.5 µm AZ5214E)
*Isotropic
|
|
Unmasked - used as a stripper
*Isotropic
|
*Anisotropic (angles sidewalls, typical around 70 dg)
|-
|-
|'''Etch rate'''
 
|-style="background:LightGrey; color:black"
!Masking material
|
|
~100 nm/min
*Photoresist
|
|
~(??) nm/min - fast etch
*None (mainly used for stripping Au)
|
*Any material that is allowed in the chamber, photoresists included
|-
 
 
|-
|-
|'''Batch size'''
|-style="background:WhiteSmoke; color:black"
!Substrate size
|
|
1-5  4" wafers at a time
*Any size and number that can go inside the beaker in use
|
|
1-5 4" wafer at a time
*Any size and number that can go inside the beaker in use
 
|
Smaller pieces glued to carrier wafer
*<nowiki>#</nowiki>1 50mm wafer
*<nowiki>#</nowiki>1 100mm wafer
*<nowiki>#</nowiki>1 150mm wafer
*<nowiki>#</nowiki>1 200mm wafer
|-
|-
|'''Size of substrate'''
 
|-
|-style="background:LightGrey; color:black"
!'''Allowed materials'''
|
|
2-6" wafers
No restrictions cross contamination wise as long as you use the right beaker and make sure that they are safe to enter in the chemicals
|
|
2-6" wafers
No restrictions cross contamination wise as long as you use the right beaker and make sure that they are safe to enter in the chemicals
|
*Silicon
*Silicon oxides
*Silicon nitrides
*Metals from the +list
*Metals from the -list
*Alloys from the above list
*Stainless steel
*Glass
*III-V materials
*Resists
*Polymers
*Capton tape
|-
|-
|}
|}

Latest revision as of 15:47, 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 Gold

Etching of Gold can be done either by wet etch, or by sputtering with ions.


Comparison of Gold Etch Methods

Au wet etch 1 Au wet etch 2 IBE (Ionfab300+)
Generel description Wet etch of Au using iodine based chemistry Wet etch of Au using Aqua Regina Sputtering of Au - pure physical etch
Etch rate range
  • ~100nm/min
  • 680 nm/min (dilute) or faster (concentrated). Mainly used for complete removal of metals
  • ~55nm/min (acceptance test)
Etch profile
  • Isotropic
  • Isotropic
  • Anisotropic (angles sidewalls, typical around 70 dg)
Masking material
  • Photoresist
  • None (mainly used for stripping Au)
  • Any material that is allowed in the chamber, photoresists included
Substrate size
  • Any size and number that can go inside the beaker in use
  • Any size and number that can go inside the beaker in use

Smaller pieces glued to carrier wafer

  • #1 50mm wafer
  • #1 100mm wafer
  • #1 150mm wafer
  • #1 200mm wafer
Allowed materials

No restrictions cross contamination wise as long as you use the right beaker and make sure that they are safe to enter in the chemicals

No restrictions cross contamination wise as long as you use the right beaker and make sure that they are safe to enter in the chemicals

  • Silicon
  • Silicon oxides
  • Silicon nitrides
  • Metals from the +list
  • Metals from the -list
  • Alloys from the above list
  • Stainless steel
  • Glass
  • III-V materials
  • Resists
  • Polymers
  • Capton tape