Anisole PPA solutions can be coated on PMMAcoMA 33 (AR-P 617). The single layers add up in this case; no mixing of layers occurs, which is a decisive prerequisite to realise defined 2- or also 3-layer systems.
Anisolic PPA solutions can be coated onto PMMA (600k, 950k), PMMAcoMA (AR-P 617) as well as on bottom resist AR-BR 5480 (alternative to PMGI). The single layers add up in each case, and virtually no mixing takes place. It is thus possible to realize well-defined two- and three-layer systems by these means.
In principle, several options exist to develop three-layer systems for the manufacture of T-gates. It is however crucial in each case that the different resists do not mix during the coating in order to ensure a coherent and well-defined layer build-up. AR-P 617 can be coated onto all PMMAs (50k – 950k) without any problems, since the resist solvent does not attack PMMAs. Vice versa can AR-P 617 also be coated with PMMA solutions in ethyl lactate or also anisole.
For multi-layer applications in e-beam lithography, Allresist offers the highly versatile bottom resist AR-BR 5460/5480. The removal rates of the bottom layer can easily be specifically adjusted by slightly changing the softbake temperature and the developer strength.