An acrylic polymer/silica hybrid resist film was investigated for fabricating a microstructure by electron-beam (EB) lithography. EB lithography on the hybrid thin film afforded a positive pattern whose depth corresponded to the EB exposure dose; this indicated that the hybrid was an analog resist and could fabricate a three-dimensional microstructure. The resist film had high heat resistance and compatibility with the underlying quartz plate, probably because of the silica component. The acrylic polymer/(RSiO1.5)(n) hybrid film showed higher EB sensitivity than a film of the crosslinked acrylic polymer and an acrylic polymer/(SiO2)(n) hybrid. Atomic force microscopy observation of the hybrid film surface showed the homogeneous dispersion of the acrylic polymer and the silica components in the hybrid film. The acrylic polymer component was EB-sensitive, whereas dispersing the acrylic polymer and silica components homogeneously also played an important role in increasing the EB sensitivity. (c) 2006 Wiley Periodicals, Inc.