Direct-Write Lithography Recipes

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Maskless Aligner (Heidelberg MLA150)

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.

Positive Resist (MLA150)

We found that positive PR's worked well with the 405nm laser - the 375nm laser would likely also work.

Resist Spin Cond. Bake Thickness Laser (nm) Exposure Dose (mJ/cm2) DeFocus 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 MLA 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 MLA design
AZ4620
SPR 220-3.0 2.5 krpm/30s 115°C/90” ~ 2.7 µm 405 325 - 4 115°C/90s AZ300MIF 60s Used MLA design
SPR 955-CM0.9 3 krpm/30s 95°C/90” ~ 0.9 µm 405 250 - 7 110°C/90s AZ300MIF 60s Used MLA design
THMR-3600HP 1.5 krpm/45s250 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.

Negative Resist (MLA150)

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

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.

Greyscale Lithography (MLA150)

AZ4620 is the manufacturer-recommended PR for greyscale litho.

Resist Spin Cond. Bake Thickness Exposure Dose (mJ/cm2) Focus Offset PEB Flood Developer Developer Time Comments
AZ4620 – krpm/30” 95°C/60” 60" AZ300MIF 60"
  • TBD