Functionalization of Fullerene for Electron Beam Nanolithography Resist

We have found that chemical modification of C60 to the methanofullerenes improves the properties as an electron beam resist. Several types of methanofullerenes exhibit good resolution and high dry-etch durability, and the films can he prepared by spin coating. Thus they can be used for nanometer scale patterning. The sensitivity is -1×10-3C/cm2, an order of magnitude higher than that of C60. The performance of the resists was demonstrated by defining 20nm features. The results of Raman measurements suggest that the exposure mechanism may be due to destruction of the C60 cage by electron irradiation. We have shown that the chemical modification of C60 molecules dramatically improves the properties as a negative e-beam resist. The methanofullerene resists can be prepared by spin coating and their sensitivity is -10-3C/cm2, an order of magnitude higher than C60 itself. These resists exhibit good resolution and high dry-etch durability. The performance of this resist was demonstrated by defining 20nm lines. It was also shown that the exposure mechanism seems to be the fragmentation by e-beam irradiation.