Specific Process Knowledge/Etch/DRIE-Pegasus/processD: Difference between revisions

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<!--Checked for updates on 14/5-2018 - ok/jmli -->
<!-- Page reviewed 9/8-2022 jmli -->
== Process D ==
{{Template:Author-jmli1}}
<!--Checked for updates on 2/02-2023 - ok/jmli -->
In this section the original version of process D is described. Since the [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange|change of the showerhead in December 2014]] an improved version of process D should be considered as well, see next section.
Mask information
* 1 µm of spin coated AZ5214E photoresist, no hardbake
* Patterned by UV lithography with the ‘Travka 50’ mask
* 50 % etch load
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
|+ '''Process A specifications'''
|+ '''Process D specifications'''
|-
|-
! Parameter
! Parameter
Line 7: Line 24:
|-
|-
! Etch rate (µm/min)   
! Etch rate (µm/min)   
| > 15
| Not specified
| 18.9
| 2.88
|-
|-
! Etched depth (µm)
! Etched depth (µm)
| 150
| 20-30
| 189.1
| 28.75
|-
|-
! Scallop size (nm)
! Scallop size (nm)
| < 800
| < 30
| 718
| 46
|-
|-
! Profile (degs)
! Profile (degs)
| 91 +/- 1
| 85 +/- 5
| 91.1
| 89.7
|-
|-
! Selectivity to AZ photoresist  
! Selectivity to AZ photoresist  
| > 150
| Not specified
| 310
| 50
|-
|-
! Undercut (µm)
! Undercut (nm)
| <1.5
| Not specified
| 0.84
| 65
|-
|-
! Uniformity (%)
! Uniformity (%)
| < 3.5
| < 3.5
| 3.0
| 4.56-0.25
|-
|-
! Repeatability (%)
! Repeatability (%)
| <4
| <4
| 0.43
|  
|-
|-
|}
|}
Line 59: Line 76:
| 2.4
| 2.4
| 2.0
| 2.0
|-
! Pressure (mtorr)
| 26
| 20
|-
! Coil power (W)
| 2500
| 2000
|-
! Platen power (W)
| 35
| 0
|-
! Cycles 
| colspan="2" | 110 (process time 08:04)
|-
! Common
| colspan="2" | Temperature 0 degs, HBC 10 torr, Long funnel, with baffle & 100 mm spacers
|}
See results in the acceptance report: [[Media:Pegasus_AcceptanceTest.pdf|here]].
== Effects on Process D of showerhead change in December 2014 ==
The effects of [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange|changing of the showerhead in December 2014]] was investigated. Patterned wafers were processed before and after and the profile of the etched features were inspected in SEM.
Process D is intended to be used for imprinting purposes - that means smooth sidewalls at relatively shallow depths (that means 'not through wafer'). It is therefore natural to exploit the faster switching capability introduced with the new showerhead for this etch process. An improved version of Process D (called Process D4) was found - see the table below.
Click on the numbers in the 'Runs' column below to see the profiles.
{| border="1" cellpadding="1" cellspacing="0" style="text-align:center;"
|-
! rowspan="2" width="100"| Recipe
! rowspan="2" width="20"| Name
! rowspan="2" width="20"| Temp.
! colspan="6" | Deposition step
! colspan="7" | Etch step
! colspan="3" | Comments
|-
! Time
! Pres.
! C<sub>4</sub>F<sub>8</sub>
! SF<sub>6</sub>
! O<sub>2</sub>
! Coil
! Time
! Pres.
! C<sub>4</sub>F<sub>8</sub>
! SF<sub>6</sub>
! O<sub>2</sub>
! Coil
! Platen
! Showerhead
! Runs
! width="100" | Key words
|-
! rowspan="7" | Process D    <!-- recipe name -->
! Original <!-- step -->
| 0      <!-- chiller temp -->
! 2      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
| 2.4      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
! Old      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/original | 1]]      <!-- link processes -->
|  <!-- keywords -->
|-
! Original <!-- step -->
| 0      <!-- chiller temp -->
! 2      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
| 2.4      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
! New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/original | 1]]      <!-- link processes -->
|  <!-- keywords -->
|-
! New Process D <!-- step -->
| 0      <!-- chiller temp -->
! 1      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
! 3      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
! New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/NewProcessD | 4]]      <!-- link processes -->
| Large undercut  <!-- keywords -->
|-
! PrD01 <!-- step -->
| 0      <!-- chiller temp -->
| 1      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
! 2.4      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
| New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/PrD01 | 2]]      <!-- link processes -->
|  <!-- keywords -->
|-
! PrD02 <!-- step -->
| 0      <!-- chiller temp -->
! 1.1      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
| 2.4      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
| New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/PrD02 | 1]]      <!-- link processes -->
|  <!-- keywords -->
|-
! PrD-3 <!-- step -->
| 0      <!-- chiller temp -->
| 1      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
! 2.5      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
| New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/PrD-3 | 1]]      <!-- link processes -->
|  <!-- keywords -->
|-
! PrD-4 <!-- step -->
| 0      <!-- chiller temp -->
| 1      <!-- dep time -->
| 20      <!-- dep pressure -->
| 150      <!-- C4F8 flow -->
| 0      <!-- SF6 flow -->
| 0    <!-- O2 flow -->
| 2000      <!-- coil power -->
! 2.2      <!-- etch time -->
| 26      <!-- etch pressure -->
| 0      <!-- C4F8 flow -->
| 275      <!-- SF6 flow -->
| 5      <!-- O2 flow -->
| 2500      <!-- coil power -->
| 35      <!-- platen power -->
| New      <!-- Showerhead -->
| [[Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange/ProcessD/PrD-4 | 1]]      <!-- link processes -->
| Best one so far!  <!-- keywords -->
|-
|}
== The new standard process Process D4 ==
{| border="2" cellpadding="2" cellspacing="1" style="text-align:center;"
|+ '''Process D4 recipe'''
|-
|-
! width="120" | Main etch (D->E) 
! width="120" | Etch
! width="120" | Dep
|-
! Gas flow (sccm)
| SF<sub>6</sub> 275 O<sub>2</sub>  5
| C<sub>4</sub>F<sub>8</sub> 150
|-
! Cycle time (secs)
| 1
| 2.2
|-
|-
! Pressure (mtorr)  
! Pressure (mtorr)  

Latest revision as of 15:44, 2 February 2023

Feedback to this page: click here


Process D

Unless otherwise stated, all content on this page was created by Jonas Michael-Lindhard, DTU Nanolab

In this section the original version of process D is described. Since the change of the showerhead in December 2014 an improved version of process D should be considered as well, see next section.

Mask information

  • 1 µm of spin coated AZ5214E photoresist, no hardbake
  • Patterned by UV lithography with the ‘Travka 50’ mask
  • 50 % etch load


Process D specifications
Parameter Specification Average result
Etch rate (µm/min) Not specified 2.88
Etched depth (µm) 20-30 28.75
Scallop size (nm) < 30 46
Profile (degs) 85 +/- 5 89.7
Selectivity to AZ photoresist Not specified 50
Undercut (nm) Not specified 65
Uniformity (%) < 3.5 4.56-0.25
Repeatability (%) <4



Process D recipe
Main etch (D->E) Etch Dep
Gas flow (sccm) SF6 275 O2 5 C4F8 150
Cycle time (secs) 2.4 2.0
Pressure (mtorr) 26 20
Coil power (W) 2500 2000
Platen power (W) 35 0
Cycles 110 (process time 08:04)
Common Temperature 0 degs, HBC 10 torr, Long funnel, with baffle & 100 mm spacers

See results in the acceptance report: here.

Effects on Process D of showerhead change in December 2014

The effects of changing of the showerhead in December 2014 was investigated. Patterned wafers were processed before and after and the profile of the etched features were inspected in SEM.

Process D is intended to be used for imprinting purposes - that means smooth sidewalls at relatively shallow depths (that means 'not through wafer'). It is therefore natural to exploit the faster switching capability introduced with the new showerhead for this etch process. An improved version of Process D (called Process D4) was found - see the table below.

Click on the numbers in the 'Runs' column below to see the profiles.

Recipe Name Temp. Deposition step Etch step Comments
Time Pres. C4F8 SF6 O2 Coil Time Pres. C4F8 SF6 O2 Coil Platen Showerhead Runs Key words
Process D Original 0 2 20 150 0 0 2000 2.4 26 0 275 5 2500 35 Old 1
Original 0 2 20 150 0 0 2000 2.4 26 0 275 5 2500 35 New 1
New Process D 0 1 20 150 0 0 2000 3 26 0 275 5 2500 35 New 4 Large undercut
PrD01 0 1 20 150 0 0 2000 2.4 26 0 275 5 2500 35 New 2
PrD02 0 1.1 20 150 0 0 2000 2.4 26 0 275 5 2500 35 New 1
PrD-3 0 1 20 150 0 0 2000 2.5 26 0 275 5 2500 35 New 1
PrD-4 0 1 20 150 0 0 2000 2.2 26 0 275 5 2500 35 New 1 Best one so far!


The new standard process Process D4

Process D4 recipe
Main etch (D->E) Etch Dep
Gas flow (sccm) SF6 275 O2 5 C4F8 150
Cycle time (secs) 1 2.2
Pressure (mtorr) 26 20
Coil power (W) 2500 2000
Platen power (W) 35 0
Cycles 110 (process time 08:04)
Common Temperature 0 degs, HBC 10 torr, Long funnel, with baffle & 100 mm spacers
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