Direct-Write Lithography Recipes
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. Sub-micron features are possible. Overexposure is recommended to avoid stitching and horiz/vert discrepancies, compensate 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||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|
|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 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;
|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 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.|
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||60s||