Optimized sputteredYBa2Cu3O7(YBCO) thin films onCeO2-buffered sapphire substrates are patterned into square lattices of submicrometer holes (antidots) with diameters of 250–450 nm and lattice parameters ofd=500–1000 nmwithout deterioration of superconducting properties. In the mixed state, matching effects between the Abrikosov vortex lattice and the artificial antidot lattice are observed. These effects are in the form of peaks or cusps in the critical current density recorded as a function of magnetic induction at integersnand specific rationalsk/lof the matching fieldBm=(&Fgr;0/d2).The experimental results are discussed in the context of existing theories. The existence of multiquanta vortices confined by the holes in YBCO films are considered. ©1997 American Institute of Physics.