A method for thermal processing a semiconductor wafer is disclosed. A rapid thermal processing (RTP) chamber encompasses a heating means, a rotation means, and a cooling system for cooling walls of said RTP chamber. A semiconductor wafer is loaded into the RTP chamber just being cooling down to a first temperature by using the cooling system. When loading the semiconductor wafer, it has a temperature that is lower than the first temperature, thereby causing a tendency of particle deposition from the walls of the RTP chamber onto the semiconductor wafer. The semiconductor wafer is pre-heated to a second temperature higher than the first temperature with the heating means, thereby eliminating the tendency of particle deposition. Upon reaching the second temperature, the rotation means is activated to start to rotate the semiconductor wafer, while the semiconductor wafer being ramped up to a third temperature.