I want to make two step e-beam lithography process:
1) Expose and develop negative ma-N 2400 pattern firstly to make special relief, which should be embedded into the next layers.
2) Coat the sample with copolymer/PMMA bi-layer, expose it and remove the negative resist features through the open windows without affecting the copolymer/PMMA pattern.
I've learnt that ma-N 2400 can be removed also in strong base solutions, such as NaOH 4-10% (I have only KOH, maybe it is even better) - see http://nanolithography.gatech.edu/resists/processing_info_Micro_Resist.pdf - but I haven't checked yet that copolymer and PMMA will alive after that treatment.
Another issue could be partial dissolution (??) of the negative features in copolymer solvent (ethyl lactate).
I will be grateful for any advice and discussion!
"Another issue could be partial dissolution (??) of the negative features in copolymer solvent (ethyl lactate)." - yes, exposed MA-N damaging by most of organic solvents but not dissolving completely.
Main idea to use sacrificial layer under MA-N to make liftoff like technique.
PMMA and MMA are dissolvable in strong base solution, such as NaOH and KOH.
MaN can be removed by TMAH solution, like photoresist developers such as RD-6 or MIF-300 before exposure. While exposed, organic solvent can still remove it. What I usually do is to dip the sample into acetone for really short time- probably 2 sec. The MaN is super thin and dissolve quickly, but the PMMA/MMA layer is minimally affected by the solvent.
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Coating