Numerical analysis was conducted to characterize particle deposition on a heated rotating semiconductor wafer with respect to wafer diameter. The particle transport mechanisms considered in this study were convection, Brownian diffusion, gravitational settling, and thermophoresis. The averaged particle deposition velocities and their radial distributions on the upper surface of the wafer were calculated from the particle concentration equation in an Eulerian frame of reference for rotating speeds of 0, 1000rpm, wafer diameters of 100, 300mm and wafer heating of =0, 5K. It was observed from the numerical results that the averaged deposition velocities on the upper surface increase, when the wafer diameter confirms increase. The comparison of the present numerical results with the available experimental results showed relatively good agreement between different studies. Keywords：Rotating Wafer, Wafer Diameter, Thermophoresis, Flow Field, Particle Deposition Velocity