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==Wet Aluminium Etch==
'''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/Wet_Aluminium_Etch click here]'''
[[Image:Wet_Al_etch.jpg|300x300px|thumb|Wet Aluminium Etch: Positioned in cleanroom 4]]
 
'''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 requires login.
 
'''All measurements on this page has been made by Nanolab staff.
 
[[Category: Equipment|Etch Wet Aluminium Etch]]
[[Category: Etch (Wet) bath|Aluminium]]
 
Wet etching of aluminium can be done using many different acids and bases. Using dilute phosphoric acid gives reasonably good control and compatibility with photoresists. Etching with dilute phosphoric acid is suitable for etching pure aluminium. If the aluminium is alloyed with other metals, other etchants may be better suited. Previously, aluminium with 1,5% silicon was used at DTU Nanolab. This alloy is no longer in use at DTU Nanolab but a suitable etchant (Aluminum etch 80-15-3-2) for this alloy is included below.
 
=Wet Aluminium Etch=
[[Image:AlEtch.jpg|300x300px|thumb|Aluminium Etch bath located in left side of Wet bench 05 in cleanroom D-3]]


Wet etching of aluminium is done with two different solutions:
Wet etching of aluminium is done with two different solutions:


# H<math>_2</math>O:H<math>_3</math>PO<math>_4</math>  1:2 at 50 <sup>o</sup>C
# H<sub>2</sub>O : H<sub>3</sub>PO<sub>4</sub>  (1:2) at 50°C
# Pre-mixed etch solution: PES 77-19-04 at 20 <sup>o</sup>C
# Pre-mixed etch solution: Aluminum etch 80-15-3-2 at 20°C
 
<br>
The first solution is always available ready made in the Aluminium Etch bath. The second solution can be mixed manually or bought pre-mixed and ready for use. Please contact DTU Nanolab if you need to use the Aluminum etch 80-15-3-2 etch mixture. Since it is used only very rarely it will probably have to be ordered when needed. The table below summarizes possibilities and parameter for the two etch mixtures.
contact Wetchem if change off bath or want to use it in a beaker.


Both solutions are used in the Aluminium etch bath shown to the right. I must be written on which one is in.


<br clear="all" />
==Comparing the two solutions==
===Comparing the two solutions===
{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"
|-


{| border="1" cellspacing="0" cellpadding="4" align="left"
|-style="background:silver; color:black"
!  
!  
! Aluminium Etch 1
! Aluminium Etch
! Aluminium Etch 2
! Etch with Aluminum etch 80-15-3-2
|-  
|-  
|General description
 
|
|-style="background:WhiteSmoke; color:black"
Etch of pure aluminium
!General description
|Etch of pure aluminium
|Etch of aluminium with 1.5% Si
|-
 
|-style="background:LightGrey; color:black"
!Location
|Bath inside Wet Bench 05 in D-3
|Bath inside Wet Bench 05 in D-3
|-
 
 
|-style="background:WhiteSmoke; color:black"
!Link to SDS
|
[https://kemibrug.dk/Kemikalier/Action?id=RCU2MHolYzIlODIlN2UlYzIlODB2JWMyJTgxJTdleiVjMiU4N0RZeiVjMiU4OXYlN2UlYzIlODElYzIlODhES0xFTEZMVGQlYzIlODclN2N2JWMyJTgzJTdlJWMyJTg4diVjMiU4OSU3ZSVjMiU4NCVjMiU4MyVjMiU4OCU1ZVlSSQ==#K Kemibrug SDS: Phosphoric acid >25%]
|
|
Etch of aluminium + 1.5% Si
[https://kemibrug.dk/Kemikalier/Action?id=RCU2MHolYzIlODIlN2UlYzIlODB2JWMyJTgxJTdleiVjMiU4N0RZeiVjMiU4OXYlN2UlYzIlODElYzIlODhETkZLR0tOS1RkJWMyJTg3JTdjdiVjMiU4MyU3ZSVjMiU4OHYlYzIlODklN2UlYzIlODQlYzIlODMlYzIlODglNWVZUkk=#K Kemibrug SDS: Phosphoric acid etch slution]
|-
|-
|Chemical solution
 
|H<math>_2</math>O:H<math>_3</math>PO<math>_4</math>  1:2
|-style="background:LightGrey; color:black"
|PES 77-19-04
!Chemical solution
|H<sub>2</sub>O:H<sub>3</sub>PO<sub>4</sub>  1:2
|Aluminum etch 80-15-3-2:
60-90 vol% H<sub>3</sub>PO<sub>4</sub> 85%
 
5-20 vol% CH<sub>3</sub>COOH 100%
 
1-5 vol% HNO<sub>3</sub> 70%
|-
|-
|Process temperature
|50 <sup>o</sup>C


|20 <sup>o</sup>C
|-style="background:WhiteSmoke; color:black"
!Process temperature
|50°C
|20°C
|-


|-style="background:LightGrey; color:black"
!Possible masking materials!
|Photoresist (1.5 µm AZ5214E)
|Photoresist (1.5 µm AZ5214E)
|-
|-


|Possible masking materials:
|-style="background:WhiteSmoke; color:black"
|
!Etch rate
Photoresist (1.5 µm AZ5214E)
|~100 nm/min (Pure Al)
|
|~60 nm/min
Photoresist (1.5 µm AZ5214E)
|-
|-
|Etch rate
 
|
|-style="background:LightGrey; color:black"
~100 nm/min (Pure Al)
!Batch size
|
|1-25 wafers at a time
~60(??) nm/min
|1-25 wafers at a time
|-
|-
|Batch size
 
|
|-style="background:WhiteSmoke; color:black"
1-25 wafers at a time
!Size of substrate
|
|4" wafers
1-25 wafer at a time
6" wafers
|4" wafers
6" wafers
|-
|-
|Size of substrate
 
|
|-style="background:LightGrey; color:black"
4" wafers
!Allowed materials
|
4" wafers
|-
|Allowed materials
|
|
*Aluminium
See the [http://labmanager.dtu.dk/function.php?module=XcMachineaction&view=edit&MachID=381 Cross Contamination Sheet] for Aluminium Etch bath
*Silicon
*Silicon Oxide
*Silicon Nitride
*Silicon Oxynitride
*Photoresist
*E-beam resist
|
|
*Aluminium
See the [http://labmanager.dtu.dk/function.php?module=XcMachineaction&view=edit&MachID=381 Cross Contamination Sheet] for Aluminium Etch bath
*Silicon
*Silicon Oxide
*Silicon Nitride
*Silicon Oxynitride
*Photoresist
*E-beam resist
|-
|-
|}
|}

Latest revision as of 07:36, 13 September 2023

Feedback to this page: click here

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 requires login.

All measurements on this page has been made by Nanolab staff.

Wet etching of aluminium can be done using many different acids and bases. Using dilute phosphoric acid gives reasonably good control and compatibility with photoresists. Etching with dilute phosphoric acid is suitable for etching pure aluminium. If the aluminium is alloyed with other metals, other etchants may be better suited. Previously, aluminium with 1,5% silicon was used at DTU Nanolab. This alloy is no longer in use at DTU Nanolab but a suitable etchant (Aluminum etch 80-15-3-2) for this alloy is included below.

Wet Aluminium Etch

Aluminium Etch bath located in left side of Wet bench 05 in cleanroom D-3

Wet etching of aluminium is done with two different solutions:

  1. H2O : H3PO4 (1:2) at 50°C
  2. Pre-mixed etch solution: Aluminum etch 80-15-3-2 at 20°C


The first solution is always available ready made in the Aluminium Etch bath. The second solution can be mixed manually or bought pre-mixed and ready for use. Please contact DTU Nanolab if you need to use the Aluminum etch 80-15-3-2 etch mixture. Since it is used only very rarely it will probably have to be ordered when needed. The table below summarizes possibilities and parameter for the two etch mixtures. contact Wetchem if change off bath or want to use it in a beaker.


Comparing the two solutions

Aluminium Etch Etch with Aluminum etch 80-15-3-2
General description Etch of pure aluminium Etch of aluminium with 1.5% Si
Location Bath inside Wet Bench 05 in D-3 Bath inside Wet Bench 05 in D-3
Link to SDS

Kemibrug SDS: Phosphoric acid >25%

Kemibrug SDS: Phosphoric acid etch slution

Chemical solution H2O:H3PO4 1:2 Aluminum etch 80-15-3-2:

60-90 vol% H3PO4 85%

5-20 vol% CH3COOH 100%

1-5 vol% HNO3 70%

Process temperature 50°C 20°C
Possible masking materials! Photoresist (1.5 µm AZ5214E) Photoresist (1.5 µm AZ5214E)
Etch rate ~100 nm/min (Pure Al) ~60 nm/min
Batch size 1-25 wafers at a time 1-25 wafers at a time
Size of substrate 4" wafers

6" wafers

4" wafers

6" wafers

Allowed materials

See the Cross Contamination Sheet for Aluminium Etch bath

See the Cross Contamination Sheet for Aluminium Etch bath

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