Extreme ultraviolet lithography based nanofabrication using a bilevel photoresist Available to Purchase

We describe the use and characterization of a bilevel photoresist for extreme ultraviolet lithography (EUVL). The bilevel photoresist consists of a combination of a commercially available polydimethylglutarimide (PMGI) bottom layer and an experimental EUVL photoresist top (imaging) layer. We measure the sensitivity of PMGI to EUV exposure dose as a function of photoresist prebake temperature, and using this data, optimize a metal liftoff process. Reliable fabrication of 700 Å thick Au structures with sub-1000 Å critical dimensions is achieved, even without the use of a Au adhesion layer, such as Ti. Using the bilevel photoresist process, we fabricate an electrode array test structure, designed for electrical characterization of molecules and nanocrystals.