Regular hole patterns have been produced on vicinal Si(111) surfaces by optical lithography, Under heat treatment in ultrahigh vacuum, morphological rearrangements of the patterned surfaces Occur. In situ light diffraction experiments were carried out during heat treatment to monitor the formation of the desired morphologies by an observation of the diffraction pattern. The surface morphology was characterized by different microscopy techniques after the heat treatment. Structured surfaces with periodic two-dimensional step arrangements and one-dimensional structures of atomically flat terraces uniformly separated by straight steps were obtained. The periodic structures extend over several mum.