A self-consistent modeling of two-dimensional and temporal (2D-t) structures of RF magnetron plasma with a metallic (copper) and a dielectric (SiO2) target is performed at 5 mTorr in argon by using plasma hybrid model consisting of a particle-in-cell/Monte Carlo (PIC/MC) simulation for electrons and the relaxation continuum (RCT) model for ions. The erosion profiles of both targets are numerically predicted through the flux velocity distribution of ions incident on the surface. The mechanism of plasma maintenance in a dielectric target is quite different from that in a metallic one. Two major differences exist in an erosion profile between both targets. One is the presence of dual peaks in the erosion profile of the dielectric target. The other is the discrepancy in the position of the maxima between incident ion flux and erosion depth on the dielectric target. These are direct influences of the radially localized structure in an interfacial sheath based on the charge accumulation on a dielectric surface.