Cylindrical nanoholes reaching 500 mu m in depth can be generated in Si(100) by immersing the wafer in a solution containing HF and H2O2 after loading the wafer with Ag nanoparticles. At the bottom of the holes, Ag particles are observed (see Figure). This suggests that the Ag particles bore into the wafer and that the pattern of the holes can be controlled by the deposition pattern of the Ag particles.