Specific Process Knowledge/Lithography

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Lithography

Lithography is a method used for transferring a pattern from a physical or digital mask onto the substrate. At DTU Nanolab we have four different types of lithography available:


Comparing lithography methods at DTU Nanolab

UV Lithography DUV Stepper Lithography E-beam Lithography Nano Imprint Lithography
Generel description Pattern transfer via ultraviolet (UV) light Pattern transfer via deep ultraviolet (DUV) light Patterning by electron beam Pattern transfer via hot embossing (HE)
Pattern size range ~1 µm and up
(resist type, thickness, and pattern dependent)
~200 nm and up
(pattern type, shape and pitch dependent)
~10-1000 nm
(and larger at high currents)
~20 nm and up
Resist type

UV sensitive:

  • AZ 5214E, AZ 4562, AZ MiR 701 (positive)
  • AZ 5214E, AZ nLOF 2020, SU-8 (negative)

DUV sensitive:

  • JSR KRF M230Y, JSR KRF M35G (positive)
  • UVN2300-0.8 (negative)

E-beam sensitive:

  • AR-P6200 CSAR, ZEP502A , PMMA (positive)
  • HSQ, mr-EBL, AR-N 7520 (negative)

Imprint polymers:

  • Topas
  • PMMA
  • mr-I 7030R
Resist thickness range ~0.5 µm to 200 µm ~50 nm to 2 µm ~30 nm to 1 µm ~100 nm to 2 µm
Typical exposure time Mask aligner: 10-180 s per wafer
Maskless aligner: 5-60 minutes per wafer

Process dependent:

  • Pattern
  • Pattern area
  • Dose

Throughput is up to 60 wafers/hour

Process dependent:

  • Dose [µC/cm2]:
  • Beam current [A]:
  • Pattern area [cm2]:

Process time [s]:

Process dependent, including heating/cooling rates
Substrate size
  • chips down to 3 mm x 3 mm
  • 50 mm wafers
  • 100 mm wafers
  • 150 mm wafers
  • 200 mm wafers
  • 100 mm wafers
  • 150 mm wafers
  • 200 mm wafers

We have cassettes fitting:

  • 4 small samples (slit openings: 20mm, 12mm, 8mm, 4mm)
  • 6 wafers of 50 mm in size
  • 3 wafers of 100 mm in size
  • 1 wafer of 150 mm in size
  • 1 wafer of 200 mm in size

Only one cassette can be loaded at a time

  • small samples
  • 50 mm wafers
  • 100 mm wafers
  • 150 mm wafers
Allowed materials Any standard cleanroom material Any standard cleanroom material

Any standard cleanroom material, except:

  • Materials that will degas
  • Graphene requires special treatment
Any standard cleanroom material


Equipment and Process Pages

Pre-lithography


Getting started with UV lithography

Resist

Substrate Pre-treatment

Coating


Automatic spin coating

Manual spin coating

Spray coating

Soft & hard baking

Exposure


UV Exposure Tools

Deep-UV Exposure

Electron Beam Exposure

Nano Imprint Lithography

Development


Manual development

SU-8 development

Semi-automatic puddle development

Automatic puddle development

Post-lithography


Descum

Lift-off

Strip


Lithography Tool Package Training

DTU Nanolab offers a Tool Package Training course for Lithography (TPT Lithography), which covers the basic theory of lithography as well as an introduction to some of the most used tools for lithographic processing.

You are required to pass this course in order to become eligible for tool training on the lithography equipment in the cleanroom facility of DTU Nanolab. The course includes theory on lithographic processes and common equipment operation and consists of lecture videos followed by a quiz for each video. Once completed successfully, you may continue to the online equipment training for the specific lithography equipment you want to use. After completing the online equipment training, you can then request hands-on training for the equipment in the cleanroom via training@nanolab.dtu.dk.

The course is available via DTU Learn. You sign up for the course by enrolling yourself in the course here


TPT lithography course contents

  • Online lecture videos
  • Online quiz for each lecture video


Learning objectives

  • Coating
  • Exposure
  • Development
  • Resist, substrates and pre-treatment
  • Post-lithography steps


Course responsible

  • Jens Hindborg Hemmingsen
  • Thomas Aarøe Anhøj

If you have questions you can contact us via lithography@nanolab.dtu.dk


Knowledge and Information about Lithography

Literature


Lecture videos

  • Lithography TPT lecture videos:
    • Current version (6 videos, 1:28 hours:minutes in total) on YouTube
    • Old version (7 videos, 2:41 hours in total) on YouTube
  • A full lecture series from a UT Austin course on microfabrication by "litho guru" Chris Mack. Half of the lectures are on (projection) lithography :-)

Training videos

Playlists on YouTube:


Manuals
NB: Access to manuals require DTU login


Process Flows