Particulate contamination is a leading cause for low yields of logic and memory devices. As circuit feature sizes decrease, submicron particles will have a greater effect on the yield. In this article, particulate contamination during the fabrication of tungsten multilevel interconnects is investigated. Particles can be carried into the chamber with the incoming gas or they may be generated due to the reactive chemistry present during processing. Tungsten films are deposited using silane (SiH4) reduction of tungsten hexafluoride (WF6). Higher deposition rates can-be obtained by increasing the deposition pressure. However, particle generation has been found to occur at higher pressures. The particle generation occurs at a SIH4:WF6 inlet mole ratio greater than 1. At high pressures and wafer temperatures (>20 Torr, 425 degrees C), particle deposition is suppressed and the particle exits the chamber with the exhaust gas. The experimental data show that the particle generation is not a result of classical homogeneous nucleation or heterogeneous nucleation. The particles are produced from a gas reaction between Si and W containing species. A theory is developed that explains the observed particle generation, as a function of process pressure, temperature and SiH4:WF6 mole ratios.