High resolution organic resists for charged particle lithography

Abstract

Exposure of resist with electron or ion beams is a common nanolithography technology which is used to fabricate electronic devices and microstructures. The resolution mainly depends on the beam size and the resolution of the resist. We have developed two new high resolution organic resists, which are calixarene derivatives. 50 keV electron beams and 260 keV Be 2ϩ ion beams were used to expose the resist, and 10 nm resolution was achieved with the Gaussian electron beam. The electron beam sensitivities of the two resists were 7 and 0.7 mC/cm 2 . By using them, we produced 10-nm-order resolution patterns, which we exposed with a Gaussian electron beam. We also achieved 10-nm-level resolution by using a low molecular weight ͑Mwϭ1100͒ polystyrene resist, almost the same Mw as that of the calixarene. The resolution of the polystyrene resist improved as lower molecular weights were used. Therefore, the resist resolution depends on the molecular weight or molecular size.

Ordered stretching of single molecules of deoxyribose nucleic acid between microfabricated polystyrene lines

“…As had been previously demonstrated, 14,15 polystyrene is an effective negative electron-beam ͑e-beam͒ resist: e-beam irradiation induces cross links between polystyrene chains, thereby making these particular chains insoluble to solvents such as xylene. Because DNA binds equally to cross linked and uncross-linked polystyrene, we can, consequently, e-beam polystyrene patterns on a substrate and stretch DNA on or between these patterns.…”

Electron Beam Modification of Polymer Nanospheres

“…Modification to polymer materials by electrons is a well-known phenomenon, which is the basis for electron beam lithography. [40][41][42][43][44][45] Depending on the molecular structure, exposure to electrons can cause either fragmentation or cross linking of the molecules, therefore affecting its 6. Nanospheres within the circles have been exposed 5 keV electrons for specified time durations.…”

Resolution limit of negative tone chemically amplified resist used for hybrid lithography: Influence of the molecular weight

“…Essentially, one way to achieve a very high resolution level can be use of a polymer matrix with shorter length chain, as was already demonstrated in previous papers. 8 The samples are described in Table I ͑detailing the molecular weight and polydispersity of each polymer and the crosslinker used͒. The same PAG was used for all formulations.…”