Fabrication of polymer nanodots with single electron patterning technology

Polymer nanodots 3-5 nm in diameter have been fabricated using conventional polymer resists. Negative-type resists of cresol novolak resins combined with crosslinkers are exposed with a uniform 50-kV electron beam. The uniform beam is considered to be a flux of ultrafine beams of individual electrons that causes crosslink reactions. By selecting electron beam doses and wet development conditions, dense patterns of polymer nanodots are successfully obtained. We call this process ''single electron patterning technology'' (SEPT). Sizes of the nanodots reflect the molecular-weight distribution characteristics of the resin polymers. A resist polymer with a small molecular distribution (polydispersity) leads to uniform dots. The dots are thought to be polymer microgels that consist of a few crosslinked resin molecules, or the molecules themselves. X-ray photoelectron spectroscopy confirms that the dots consist of resist polymers. (C) 1996 American Institute of Physics.