Direct-Write Lithography Recipes: Difference between revisions

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[[category: Lithography]]
{{recipes|Lithography}}
[[category: Recipes]]
{{WIP}}
__TOC__


Photolithography Recipes for the Heidelberg MLA150 will go here.
==[[Maskless Aligner (Heidelberg MLA150)]]==
For CAD design tips and requirements, see these pages:


*[[MLA150 - Design Guidelines|Design Guidelines + Tips]] - ''useful info for designing your CAD files, alignment marks etc.''
== Positive Resist (MLA150) ==
*[[MLA150 - CAD Files and Templates|CAD Files and Templates]] - example CAD files etc.
General notes: Hotplates used, filters, laser wavelengths, etc.


Photolithography Recipes for the [[Maskless Aligner (Heidelberg MLA150)|Heidelberg MLA150]]. All recipes were characterized on blank Silicon wafers. For different substrate coatings/materials, you will likely need to run a focus-exposure matrix ("series" exposure mode), using our params as a starting point.
== Negative Resist (MLA150) ==

General notes: Hotplates used, filters, laser wavelengths, etc.
These recipes use the same spin and bake params as our contact aligner and stepper recipes, using built-in hotplates on the photoresist spinner benches.

'''''Any I-Line PR is usable''''', although we only characterized a select few below. Run your own Focus-Exposure Matrix to characterize a new PR.

'''<u>Note:</u>''' On this tool, it is common to have to run a Focus-Exposure Matrix (aka. FEM), via "''Series''" exposure mode, for each new layer structure and/or critical feature size. The layer structure can strongly affect the exposure parameters. See the [[ASML Stepper 3 Standard Operating Procedure#Tips for FEM analysis|FEM Analysis Tips page]] for how to choose the proper exposure parameters.

The [[MLA150 - Troubleshooting#Out Of Focus Exposures|'''MLA''' '''Troubleshooting > Out-of-Focus Exposures''']] section can help you avoid bad exposures, please read it!

===Positive Resist (MLA150)===
''We found that positive PR's worked well with the 405nm laser - the 375nm laser would likely also work. Sub-micron features are possible. Overexposure is recommended to avoid stitching and horiz/vert discrepancies; compensate for widening/narrowing using CD Bias [[MLA150 - Design Guidelines#High-Resolution Writing|as described here]].''

Note: calibrations done with the "HIMT design" will show higher dose, due to using only dark-field line/space patterns.

{| class="wikitable" style="border: 1px solid #D0E7FF; background-color:#ffffff; text-align:center;" border="1"
|- bgcolor="#D0E7FF"
! width="100" |Resist
! width="100" |Spin Cond.
! width="75" |Bake
! width="75" |Thickness
!Laser (nm)
! width="125" |Exposure Dose (mJ/cm<sup>2</sup>)
! width="100" |DeFocus
!Rehydrate*
! width="75" |PEB**
! width="100" |Developer
! width="125" |Developer Time
! width="300" |Comments
|-
|[[Media:AXP4000pb-Datasheet.pdf|AZ4110]]
|4 krpm, 30s
|95°C, 60s
|~ 1.1 µm
|405
|240
|5
|
|''none''
|AZ400K:DI 1:4
|50s
|Used HIMT design (good for isolated lines 0.8-1um)
|-

|[[Media:AXP4000pb-Datasheet.pdf|AZ4330]]
|4 krpm, 30s
|95°C, 60s
|~ 3.3 µm
|405
|320
|6
|
|''none''
|AZ400K:DI 1:4
|90s
|Used HIMT design
|-
|[[Media:AXP4000pb-Datasheet.pdf|AZ4620]]
|
|
|
|
|
|
|
|
|
|
|
|-
|[[Media:SPR220-Positive-Resist-Datasheet.pdf|SPR 955-1.8]]
|4 krpm, 30s
|95°C, 90s
|~ 1.8 µm
|405
|210
|10
|
|110°C, 90s
|AZ300MIF
|60s
|Used UCSB design (1um dense lines)
|-
|[[Media:SPR220-Positive-Resist-Datasheet.pdf|SPR 220-3.0]]
|2.5 krpm, 30s
|115°C, 90s
|~ 2.7 µm
|405
|325
| - 4
|
|115°C, 90s
|AZ300MIF
|60s
|Used HIMT design. 0.6-0.9µm line/space.
|-
|[[Media:SPR220-Positive-Resist-Datasheet.pdf|SPR 220-7.0]]
|3.5 krpm, 30s
|105°C/2min
Cool 1min
|~ 7.0µm
|375
|~550mJ
| -20
|>1hr
|115°C, 90s
|AZ300MiF
|70s
|Rehydration after exposure is necessary, to prevent bubbles at PEB.
|-
|[[Media:SPR955-Positive-Resist-Datasheet.pdf|SPR 955-CM0.9]]
|3 krpm, 30s
|95°C, 90s
|~ 0.9 µm
|405
|250
| - 7
|
|110°C, 90s
|AZ300MIF
|60s
|Used HIMT design
|-
|[[Media:3600 D, D2v Spin Speed Curve.pdf|THMR-3600HP]]
|1.5 krpm, 45s;
250 rpm/s
|100°C, 60s
|0.430µm
|405
|180–220
|<nowiki>-4</nowiki>
|
|100°C, 60s
|AZ300MiF
|20s
|~0.4nm line/space:

lower dose for clear-field, higher dose for dark-field.
|-
| colspan="12" |*''Rehydration'': After exposure, leave sample in lab air (ok to cover in tray, with tinfoil). Allows water vapor in air to diffuse into PR to complete chemical reaction.
<nowiki>**</nowiki>''PEB: Post-exposure bake'': after exposure, before develop
|}

===Negative Resist (MLA150)===
''We found that all the negative PR's we tested required the 375nm in order to be fully exposed with reasonable dose/time.''

{| class="wikitable" style="border: 1px solid #D0E7FF; background-color:#ffffff; text-align:center;" border="1"
|- bgcolor="#D0E7FF"
! width="100" |Resist
! width="100" |Spin Cond.
! width="75" |Bake
! width="75" |Thickness
!Laser (nm)
! width="125" |Exposure Dose (mJ/cm<sup>2</sup>)
! width="100" |DeFocus
! width="75" |PEB*
! width="75" |Flood**
! width="100" |Developer
! width="125" |Developer Time
! width="300" |Comments
|-
|[[Media:AZ5214-Negative-Resist-Datasheet.pdf|AZ5214]]**
|6 krpm, 30s
|95°C, 60s
|~ 1.0 µm
|375
|35
| - 5
|110°C, 60s
|60"
|AZ300MIF
|60s
|Used UCSB design. Good for up to ~1.3um open line space.
|-
|[[Media:AZnLOF2020-Negative-Resist-Datasheet.pdf|AZnLOF2020]]
|4 krpm, 30s
|110°C, 60s
|~ 2.1µm
|375
|340
| - 3
|110°C, 60s
|''none''
|AZ300MIF
|90s
|Used UCSB design. Good for 2um open line space.
|-
|[[Media:SU-8-2075-revA.pdf|SU-8 2075]]
|
|
|~70µm
|375
|
|
|
|
|
|
|Extremely viscous. Pour into a wide-mouthed bottle, dispense directly from bottle. Replace napkin at end.
|-
| colspan="12" |*PEB: post-exposure bake. For AZ 5214-IR, this performs Image Reversal
<nowiki>**</nowiki> To use AZ5214 as a negative PR requires Flood Exposure with the [[Contact Aligner (SUSS MA-6)|MA6]] or [[Suss Aligners (SUSS MJB-3)|MJB]] aligner '''''after PEB''''', before developing. See here for a [[AZ5214 - Basic Process|basic AZ5214 process]], it is different than typical negative resists.
|}

===Greyscale Lithography (MLA150)===
''AZ4620 is the manufacturer-recommended PR for greyscale litho.''

Please see the [[MLA150 - Design Guidelines#Limitations%20.26%20Workarounds|'''MLA150 - Greyscale Design Guidelines & Limitation''']]
{| class="wikitable" style="border: 1px solid #D0E7FF; background-color:#ffffff; text-align:center;" border="1"
|- bgcolor="#D0E7FF"
! width="100" |Resist
! width="100" |Spin Cond.
! width="75" |Bake
! width="75" |Thickness
!Laser
! width="125" |Exposure Dose (mJ/cm<sup>2</sup>)
! width="100" |Focus Offset
!Rehydrate*
! width="75" |PEB**
! width="100" |Developer
! width="125" |Developer Time
!Reflow***
! width="300" |Comments
|-
|[[Media:Az p4620 photoresist data package.pdf|AZ4620]]
|? krpm/30”
|95°C, 60”
|
|
|
|
|
|
|AZ300MIF
|60s
|
| align="left" |''To Be Added''
|-
|[[Media:SPR220-Positive-Resist-Datasheet.pdf|SPR 220-7.0]]
|3.5 krpm, 30s
|105°C/2min
Cool 1min
|~ 7.0µm
|375
|~624mJ to clear large mm-area,
520mJ to clear ~5µm lines.
| -20
|≥1hr
|115°C, 90s
|AZ300MiF
|70s
|TBD
|<small>Author Credit:</small>
*<small>Patrick Curtis, 2022</small>
*<small>Biljana Stamenic 2023</small>
*<small>Demis D. John 2023</small>
|-
|
| colspan="12" |Notes on SPR 220-7 Greyscale: Rehydration after exposure is necessary, to prevent bubbles at PEB.
Stitching leaves ridges in Y-direction with ~5% height of removed PR depth. Can be reduced via reflow, but significantly affects PR profile.

<small>Author Credit: Patrick Curtis, 2022 & Biljana Stamenic 2023 & Demis D. John 2023; Please see our [[Frequently Asked Questions#Publications acknowledging the Nanofab|publications policy]].</small>
|-
| colspan="13" |*''Rehydration'': After exposure, leave sample in lab air (ok to cover in tray, with tinfoil). Allows water vapor in air to diffuse into PR to complete chemical reaction.
<nowiki>**</nowiki>''PEB: Post-exposure bake'': after exposure, before develop

<nowiki>***</nowiki>''Reflow'': To smooth out stitching lines. Will change sharp vertical profiles considerably, only good for gradually-sloped profiles.
|}

Latest revision as of 19:10, 12 November 2024

Maskless Aligner (Heidelberg MLA150)

For CAD design tips and requirements, see these pages:

Photolithography Recipes for the Heidelberg MLA150. All recipes were characterized on blank Silicon wafers. For different substrate coatings/materials, you will likely need to run a focus-exposure matrix ("series" exposure mode), using our params as a starting point.

These recipes use the same spin and bake params as our contact aligner and stepper recipes, using built-in hotplates on the photoresist spinner benches.

Any I-Line PR is usable, although we only characterized a select few below. Run your own Focus-Exposure Matrix to characterize a new PR.

Note: On this tool, it is common to have to run a Focus-Exposure Matrix (aka. FEM), via "Series" exposure mode, for each new layer structure and/or critical feature size. The layer structure can strongly affect the exposure parameters. See the FEM Analysis Tips page for how to choose the proper exposure parameters.

The MLA Troubleshooting > Out-of-Focus Exposures section can help you avoid bad exposures, please read it!

Positive Resist (MLA150)

We found that positive PR's worked well with the 405nm laser - the 375nm laser would likely also work. Sub-micron features are possible. Overexposure is recommended to avoid stitching and horiz/vert discrepancies; compensate for widening/narrowing using CD Bias as described here.

Note: calibrations done with the "HIMT design" will show higher dose, due to using only dark-field line/space patterns.

Resist Spin Cond. Bake Thickness Laser (nm) Exposure Dose (mJ/cm2) DeFocus Rehydrate* PEB** Developer Developer Time Comments
AZ4110 4 krpm, 30s 95°C, 60s ~ 1.1 µm 405 240 5 none AZ400K:DI 1:4 50s Used HIMT design (good for isolated lines 0.8-1um)
AZ4330 4 krpm, 30s 95°C, 60s ~ 3.3 µm 405 320 6 none AZ400K:DI 1:4 90s Used HIMT design
AZ4620
SPR 955-1.8 4 krpm, 30s 95°C, 90s ~ 1.8 µm 405 210 10 110°C, 90s AZ300MIF 60s Used UCSB design (1um dense lines)
SPR 220-3.0 2.5 krpm, 30s 115°C, 90s ~ 2.7 µm 405 325 - 4 115°C, 90s AZ300MIF 60s Used HIMT design. 0.6-0.9µm line/space.
SPR 220-7.0 3.5 krpm, 30s 105°C/2min

Cool 1min

~ 7.0µm 375 ~550mJ -20 >1hr 115°C, 90s AZ300MiF 70s Rehydration after exposure is necessary, to prevent bubbles at PEB.
SPR 955-CM0.9 3 krpm, 30s 95°C, 90s ~ 0.9 µm 405 250 - 7 110°C, 90s AZ300MIF 60s Used HIMT design
THMR-3600HP 1.5 krpm, 45s;

250 rpm/s

100°C, 60s 0.430µm 405 180–220 -4 100°C, 60s AZ300MiF 20s ~0.4nm line/space:

lower dose for clear-field, higher dose for dark-field.

*Rehydration: After exposure, leave sample in lab air (ok to cover in tray, with tinfoil). Allows water vapor in air to diffuse into PR to complete chemical reaction.

**PEB: Post-exposure bake: after exposure, before develop

Negative Resist (MLA150)

We found that all the negative PR's we tested required the 375nm in order to be fully exposed with reasonable dose/time.

Resist Spin Cond. Bake Thickness Laser (nm) Exposure Dose (mJ/cm2) DeFocus PEB* Flood** Developer Developer Time Comments
AZ5214** 6 krpm, 30s 95°C, 60s ~ 1.0 µm 375 35 - 5 110°C, 60s 60" AZ300MIF 60s Used UCSB design. Good for up to ~1.3um open line space.
AZnLOF2020 4 krpm, 30s 110°C, 60s ~ 2.1µm 375 340 - 3 110°C, 60s none AZ300MIF 90s Used UCSB design. Good for 2um open line space.
SU-8 2075 ~70µm 375 Extremely viscous. Pour into a wide-mouthed bottle, dispense directly from bottle. Replace napkin at end.
*PEB: post-exposure bake. For AZ 5214-IR, this performs Image Reversal

** To use AZ5214 as a negative PR requires Flood Exposure with the MA6 or MJB aligner after PEB, before developing. See here for a basic AZ5214 process, it is different than typical negative resists.

Greyscale Lithography (MLA150)

AZ4620 is the manufacturer-recommended PR for greyscale litho.

Please see the MLA150 - Greyscale Design Guidelines & Limitation

Resist Spin Cond. Bake Thickness Laser Exposure Dose (mJ/cm2) Focus Offset Rehydrate* PEB** Developer Developer Time Reflow*** Comments
AZ4620 ? krpm/30” 95°C, 60” AZ300MIF 60s To Be Added
SPR 220-7.0 3.5 krpm, 30s 105°C/2min

Cool 1min

~ 7.0µm 375 ~624mJ to clear large mm-area,

520mJ to clear ~5µm lines.

-20 ≥1hr 115°C, 90s AZ300MiF 70s TBD Author Credit:
  • Patrick Curtis, 2022
  • Biljana Stamenic 2023
  • Demis D. John 2023
Notes on SPR 220-7 Greyscale: Rehydration after exposure is necessary, to prevent bubbles at PEB.

Stitching leaves ridges in Y-direction with ~5% height of removed PR depth. Can be reduced via reflow, but significantly affects PR profile.

Author Credit: Patrick Curtis, 2022 & Biljana Stamenic 2023 & Demis D. John 2023; Please see our publications policy.

*Rehydration: After exposure, leave sample in lab air (ok to cover in tray, with tinfoil). Allows water vapor in air to diffuse into PR to complete chemical reaction.

**PEB: Post-exposure bake: after exposure, before develop

***Reflow: To smooth out stitching lines. Will change sharp vertical profiles considerably, only good for gradually-sloped profiles.

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