Specific Process Knowledge/Lithography/nLOF: Difference between revisions

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{{:Specific Process Knowledge/Lithography/authors_generic}}
'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/nLOF click here]'''
[[Category: Lithography|Resist]]
[[Category: Resist|AZ nLOF 2020]]
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'''Typical spin parameters:'''
'''Typical spin parameters:'''
*Spin off: 30-60 s
*Spin off: 30-60 s
*Soft bake: 60s @ 110°C
*Soft bake: 60 s @ 110°C


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*PEB time: 60 s
*PEB time: 60 s


The recommended PEB for nLOF is 60s at 110°C, regardless of resist film thickness.
 
The recommended PEB for nLOF is 60 seconds at 110°C, regardless of resist film thickness.
 


'''PEB baking time investigation:'''
'''PEB baking time investigation:'''
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A 2 µm nLOF resist film is fully developed in 20-30 s in 2.38% TMAH (AZ 726 MIF). However, the development can be continued to 60 s in order to get a more negative resist profile (due to increased under-cut).
A 2 µm nLOF resist film is fully developed in ~30 s in 2.38% TMAH (AZ 726 MIF). However, the development can be continued to 60 s in order to get a more negative resist profile (due to increased under-cut).

Latest revision as of 14:30, 5 April 2023

This section, including all images and pictures, is created by DTU Nanolab staff unless otherwise stated.

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Resist description

AZ nLOF 2020 is a negative UV photoresist, suitable for lift-off processes.

Spin coating

Spin curves for AZ nLOF 2020 using a 30s spin-off, and a 60s@110°C softbake

Typical spin parameters:

  • Spin off: 30-60 s
  • Soft bake: 60 s @ 110°C


Post-exposure bake

Typical PEB parameters:

  • PEB temperature: 110°C
  • PEB time: 60 s


The recommended PEB for nLOF is 60 seconds at 110°C, regardless of resist film thickness.


PEB baking time investigation: While 60 s @ 110°C is adequate for Si substrates, less thermally conductive substrates (glass, III-V materials, chips bonded to carrier), have shown problems using the standard PEB recipe.
These problems were largely solved by increasing the PEB time to 120 s. Tests (on Aligner: Maskless 02) have shown that the lithographic performance of nLOF on Si is improved when using 120 s @ 110°C PEB (less stitching, less bias, more negative profile). A small report on the tests can be found here.

Development

Development speed:

  • Puddle development in 2.38% TMAH (AZ 726 MIF): ~4 µm/min


A 2 µm nLOF resist film is fully developed in ~30 s in 2.38% TMAH (AZ 726 MIF). However, the development can be continued to 60 s in order to get a more negative resist profile (due to increased under-cut).