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== The ICP Metal Etcher in short ==
'''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/ICP_Metal_Etcher click here]'''
<!--Page reviewed by jmli 9/8-2022  -->


Despite its name the metal etcher doesn't etch metals in general. Currently, the list of metals that you can etch is quite short:
[[Category: Equipment |Etch ICP Metal]]
* aluminium
[[Category: Etch (Dry) Equipment|ICP metal]]
* titanium
* chromium
Over time it is our intention to add other materials to the list such as molybdenum, tungsten, titaniumtungsten, titaniumoxides or piezo-materials such as ZnO. However, currently you are not even allowed to expose other metals to the plasma. To etch other metals use the [[Specific Process Knowledge/Etch/IBE/IBSD Ionfab 300|IBE/IBSD Ionfab 300]].


== Recipes on the Metal Etcher ==
== The ICP Metal Etcher ==


=== Aluminium etch ===
[[Image:ICP-Metal-Etcher.jpg |300x300px|thumb|The SPTS ICP Metal Etcher in the DTU Nanolab cleanroom B-1]]


The aluminium etch has two steps:
Name: PRO ICP <br>
Vendor: STS (now SPTS) <br>
The ICP Metal Etcher allows you to dry etch a small set of metals that includes aluminium, titanium, chromium, titanium tungsten and molybdenum (along with the related oxides and nitrides). It is, despite its name, strictly forbidden to etch (or expose to plasma) other metals. In order to do so use the [[Specific Process Knowledge/Etch/IBE&frasl;IBSD Ionfab 300|IBE/IBSD Ionfab 300]].


; Breakthrough
'''The user manual, user APV and contact information can be found in LabManager:'''
: The breakthrough step is designed to break through the native aluminium oxide layer that is present on all aluminium surfaces. The duration of this step should remain fixed.


; Main
Equipment info in [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=266 LabManager]
: The main step etches bulk aluminium.
 
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
|+ '''Al etch'''
|-
! rowspan="2" | Parameter
! colspan="2" | Process step
|-
! width="200" | Breakthrough
! width="200" | Main
|-
! Time (secs)
| 20
| 40 (variable)
|-
! HBr (sccm)
| -
| 15
|-
! Cl<sub>2</sub> (sccm)
| 20
| 25
|-
! Pressure (mTorr)
| 4,  Strike 3 secs @ 15 mTorr???
| 1
|-
! Coil power (W)
| 600
| 500
|-
! Platen power (W)
| 125
| 100
|-
! Temperature (<sup>o</sup>C)
| 20
| 20
|-
! Spacers (mm)
| 30
| 30
|-
|}
 
=== Titanium etch ===
 
 
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
|+ '''Ti etch'''
|-
! Parameter
! width="200" | Process 1
! width="200" | Process 2
|-
! Cl<sub>2</sub> (sccm)
| 30
| 30
|-
! HBr (sccm)
| -
| -
|-
! Pressure (mTorr)
| 3,  Strike 3 secs @ 15 mTorr???
| 3
|-
! Coil power (W)
| 800
| 900
|-
! Platen power (W)
| 100
| 50
|-
! Temperature (<sup>o</sup>C)
| 20
| 20
|-
! Spacers (mm)
| 30
| 30
|-
! Etch rate (nm/min)
| 152
| 64
|-
!AZ resist selectivity
| 0.67
| 0.83
|-
|}
 
 
===Chromium etch===
The Chromium etch has ONLY been carried out on the following substrate stack:
The Chromium is sputter deposited onto a 2" quartz wafer and pattered by e-beam with Zep520A resist.
This 2" QZ wafer is bonded with crystal bond to a 65mmx65mm quartz plate with the thickness: 6.35mm.
This QZ plate is bonded to a Si wafer.
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
|+ '''Cr etch'''
|-
! Parameter
! width="200" | Cr etch
|-
! Cl<sub>2</sub> (sccm)
| 65
|-
! O<sub>2</sub> (sccm)
| 15
|-
! Pressure (mTorr)
| 15
|-
! Coil power (W)
| 500
|-
! Platen power (W)
| 15
|-
! Temperature (<sup>o</sup>C)
| 50 (no back side cooling)
|-
! Spacers (mm)
| 100
|-
! Etch rate (nm/min)
| ~40
|-
!Zep520A resist selectivity
| ~0.9
|-
|}


==Process information==


'''Standard recipes'''


==Etching of nanostructures in silicon using the ICP Metal Etcher==
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/Aluminium|Etch of aluminium]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/Titanium|Etch of titanium]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/Chromium|Etch of chromium]]


A series of experiments with etching nanostructures in silicon has been carried out. The common process parameters are:
'''Other etch recipes'''
; Substrates
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/Barc Etch|Barc Etch]]
: A pattern containing 30 nm, 60 nm, 90 nm, 120 nm and 150 nm wide lines has been transferred using E-beam lithography onto three separate batches of 2" wafers (with three different thicknesses of zep resist). In order to make sure that the narrowest features are fully opened they are intentionally over-exposed in the E-beam writer (400 muC/cm2) causing the lines to widen. The resist profiles are:
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/silicon|Etch of silicon]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/nanoetch/180nmzep|The 180 nm zep resist profiles (Wafer WF_2B1_feb06_2011)]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/silicon oxide|Etch of silicon oxide]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/nanoetch/340nmzep|The 340 nm zep resist profiles (Wafer WF_2C1_feb2011)]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/silicon nitride|Etch of silicon nitride]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/nanoetch/211nmzep|The 211 nm zep resist profiles (Wafer WF_2E02_mar23_2011)]]
*[[Specific Process Knowledge/Etch/Titanium Oxide/ICP metal|Etch of Titanium Oxide]]
The exposed area is very small. The 211 nm batch has the same lines distributed in a different way that allows you monitor the progress of the etch in three different durations by cleaving off a piece of the wafer 3 times.
*[[Specific Process Knowledge/Etch/Aluminum Oxide/Al2O3 Etch with ICP Metal|Al<sub>2</sub>O<sub>3</sub> Etch]]
After E-beam exposure the wafers have been developed: N50 for 2 minutes followed by 30 seconds of IPA.


; Substrate mounting
'''End point detection'''
: The 2" wafers are mounted with crystalbond in the center of 4" Si carriers that have an oxide layer facing the plasma.
*[[/Examples of End point detection|Examples of End point detection]]


; Conditioning the process chamber


==An overview of the performance of the ICP Metal Etcher and some process related parameters==


{| border="2" cellspacing="1" cellpadding="3" style="text-align:center;"
{| border="2" cellspacing="0" cellpadding="2"  
!Recipe Sinano
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano3|3.0]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano31|3.1]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano32|3.2]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan33|3.3]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano34|3.4]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano4|4.0]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano35|3.5]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano36|3.6]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan33-2|3.3]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan37|3.7]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan331|3.31]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan331-2|3.31]]
![[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinan332|3.32]]
|-
|-
!Cl<sub>2</sub> (sccm)
!style="background:silver; color:black;" align="left"|Purpose
|0
|style="background:LightGrey; color:black"|Dry etch of
|0
|style="background:WhiteSmoke; color:black"|
|0
* Metals such as aluminium, chromium and titanium and the related oxides and nitrides
|0
* Metals such as molybdenum, tungsten, titanium tungsten
|0
|20
|15
|15
|0
|0
|0
|0
|0
|-
|-
!BCl<sub>3</sub> (sccm)
!style="background:silver; color:black" align="left" valign="top" rowspan="2"|Performance
|5
|style="background:LightGrey; color:black"|Etch rates
|3
|style="background:WhiteSmoke; color:black"|
|5
* Aluminium : ~350 nm/min (depending on features size and etch load)
|5
|5
|0
|5
|5
|5
|5
|5
|5
|5
|-
|-
!HBr (sccm)
|style="background:LightGrey; color:black"|Anisotropy
|15
|style="background:WhiteSmoke; color:black"|
|17
*Good
|15
|15
|15
|0
|0
|0
|15
|15
|15
|15
|15
|-
|-
! Coil power (W)
!style="background:silver; color:black" align="left" valign="top" rowspan="2"|Process parameter range
|900 L
|style="background:LightGrey; color:black"|Process pressure
|900 F
|style="background:WhiteSmoke; color:black"|
|900 F
*~0.1-95 mTorr
|900 F
|900 F
|900 L
|900 L
|900 F
|900 F
|900 L
|900 F
|900 F
|900 F
|-
|-
!Platen power (W)
|style="background:LightGrey; color:black"|Gas flows
|50
|style="background:WhiteSmoke; color:black"|
|50
{|
|60
| SF<sub>6</sub>: 0-100 sccm
|75
| O<sub>2</sub>: 0-100 sccm
|90
|60
|60
|60
|75
|60
|75
|75
|30
|-
|-
! Pressure (mtorr)
| C<sub>4</sub>F<sub>8</sub>: 0-100 sccm
|2
| Ar: 0-300 sccm
|2
|2
|2
|2
|2
|5
|10
|2
|10
|2
|2
|2
|-
|-
!Temperature (<sup>o</sup>C)
| CF<sub>4</sub>: 0-100 sccm
| 20
| H<sub>2</sub>: 0-30 sccm
| 20
| 20
| 20
| 20
| 20
| 20
| 20
| 20
| 50
| 50
| 50
| 50
|-
|-
! Spacers (mm)
| CH<sub>4</sub>: not working
| 100
| BCl<sub>3</sub>: 0-90 sccm
| 100
| 100
| 100
| 100
| 100
| 100
| 100
| 100
| 100
| 100
| 30
| 100
|-
|-
! Process time (s)
| Cl<sub>2</sub>: 0-100 sccm
|150
| HBr: 0-100 sccm
|180
|}
|120
|180
|120
|90
|120
|180
|300
|180
|180
|180
|180
|-
|-
! colspan="14" align="center"| Etch rates (nm/min)
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Substrates
|-
|style="background:LightGrey; color:black"|Batch size
| Averages||311||104||92||105||116||169||108||79||101||66||91||98||59
|style="background:WhiteSmoke; color:black"|
|-
*1 6" wafer per run
| Std. Dev||44||15||15||21||22||9||11||31||29||4||28||18||12
*1 4" wafer per run
|-
*1 2" wafer per run
! colspan="14" align="center"| Zep etch rate (nm/min)
*Or several smaller pieces on a carrier wafer
|-
| || ||30||40||51||67|| || ||45||59|| ||53||36||19
|-
! colspan="14" align="center"| Sidewall angle (degrees)
|-
| Averages||82||82||82||82||82||84||81||83||83||85||80||83||79
|-
| Std. Dev||2||2||1||1||1||1||1||2||2||1||3||2||2
|-
! colspan="14" align="center"| CD loss (nm pr edge)
|-
| Averages||65||-11||-15||-2||-11||67||63||-29||-5||-29||10||-14||-17
|-
| Std. Dev||30||5||2||4||3||29||27||6||5||8||7||8||10
|-
! colspan="14" align="center"| Bowing (nm)
|-
| Averages||31||31||15||6||5||22||12||15||28||13||25||1||-2
|-
| Std. Dev||6||7||3||6||4||5||2||6||9||7||5||2||2
|-
! colspan="14" align="center"| Bottom curvature
|-
| Averages||-9||-6||-9||-11||-9||9||-4||-8||-24||-2||-9||-13||-10
|-
| Std. Dev||22||19||19||11||7||17||15||15||12||15||13||17||18
|-
|-
| style="background:LightGrey; color:black"|Substrate material allowed
|style="background:WhiteSmoke; color:black"|
*Silicon wafers
**with layers of silicon oxide or silicon (oxy)nitride
*Quartz wafers
|-
| style="background:LightGrey; color:black"|Possible masking material
|style="background:WhiteSmoke; color:black"|
*Photoresist/e-beam resist
*PolySilicon, Silicon oxide or silicon (oxy)nitride
*Aluminium, titanium or chromium
|-
|}
|}
*[[Specific Process Knowledge/Etch/DRIE-Pegasus/nanoetch|Nanoetch on DRIE-Pegasus]]
*[[Specific Process Knowledge/Etch/ICP Metal Etcher/Sinano1|1 - the first nanoetch]]

Latest revision as of 09:37, 24 April 2023

Feedback to this page: click here

The ICP Metal Etcher

The SPTS ICP Metal Etcher in the DTU Nanolab cleanroom B-1

Name: PRO ICP
Vendor: STS (now SPTS)
The ICP Metal Etcher allows you to dry etch a small set of metals that includes aluminium, titanium, chromium, titanium tungsten and molybdenum (along with the related oxides and nitrides). It is, despite its name, strictly forbidden to etch (or expose to plasma) other metals. In order to do so use the IBE/IBSD Ionfab 300.

The user manual, user APV and contact information can be found in LabManager:

Equipment info in LabManager

Process information

Standard recipes

Other etch recipes

End point detection


An overview of the performance of the ICP Metal Etcher and some process related parameters

Purpose Dry etch of
  • Metals such as aluminium, chromium and titanium and the related oxides and nitrides
  • Metals such as molybdenum, tungsten, titanium tungsten
Performance Etch rates
  • Aluminium : ~350 nm/min (depending on features size and etch load)
Anisotropy
  • Good
Process parameter range Process pressure
  • ~0.1-95 mTorr
Gas flows
SF6: 0-100 sccm O2: 0-100 sccm
C4F8: 0-100 sccm Ar: 0-300 sccm
CF4: 0-100 sccm H2: 0-30 sccm
CH4: not working BCl3: 0-90 sccm
Cl2: 0-100 sccm HBr: 0-100 sccm
Substrates Batch size
  • 1 6" wafer per run
  • 1 4" wafer per run
  • 1 2" wafer per run
  • Or several smaller pieces on a carrier wafer
Substrate material allowed
  • Silicon wafers
    • with layers of silicon oxide or silicon (oxy)nitride
  • Quartz wafers
Possible masking material
  • Photoresist/e-beam resist
  • PolySilicon, Silicon oxide or silicon (oxy)nitride
  • Aluminium, titanium or chromium
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