UPDATES:
- Kathryn McGill (CNF Fellow), 6/12/15
Recipe
Chip Spinning:
- spin 4% 495 PMMA (solvent anisole) @ 3000 rpm, 1000 ramp, 60 s (resist will be ~150 nm thick)
- bake @ 170 °C for 15 min
- spin 2% 950 PMMA (solvent MIBK) @ 3000 rpm, 1000 ramp, 60 s (resist will be ~50 nm thick)
- bake @ 170 °C for 15 min
E-beam Writing on the Nabity:
- Measure the current in pA for each aperture setting (typically 10 µm aperture for fine contacts & 60 µm aperture for probe (big) contact pads).
- Set up run files (see screenshots below).
Parameters common to all run files:
- gun @ 20 kV
- 900 magnification
General Parameters:
- Non-stop writing mode ⇒ yes
- Disable automated stage control ⇒ no
- Disable digital SEM control ⇒ no
- Disable x-y focus mode ⇒ yes
- Enable global rotation correction ⇒ no
- alignment windows: counts of 15; center-to-center & line spacing of 50 nm
- fine contacts: continuous write; center-to-center & line spacing of 5 nm; 300 µC/cm^2 area dose
- big contact pads: continuous write; center-to-center & line spacing of 30 nm; 300 µC/cm^2 area dose
Development
45 sec in 1:3 MIBK:IPA (shake chip back-and-forth in soln) & quench in IPA; N2 dry
Liftoff
1:1 methylene chloride:acetone overnight
Walk-through
step 1 - copy gds file into this directory:
