In this work, the nucleation and growth of InAs nanowires on patterned SiO(2)/Si(111) substrates is studied. It is found that the nanowire yield is strongly dependent on the size of the etched holes in the SiO(2), where openings smaller than 180 nm lead to a substantial decrease in nucleation yield, while openings larger than ≈500nm promote nucleation of crystallites rather than nanowires. We propose that this is a result of indium particle formation prior to nanowire growth, where the size of the indium particles, under constant growth parameters, is strongly influenced by the size of the openings in the SiO(2) film. Nanowires overgrowing the etched holes, eventually leading to a merging of neighboring nanowires, shed light into the growth mechanism.