Thermal modeling of tubular horizontal hot-wall low pressure chemical vapor deposition reactors

Abstract

Low pressure chemical vapor deposition (LPCVD) reactors are intensively used in the microelectronics industry for depositing thin films of polysilicon. In this paper, a thermal model is presented, involving computations of the water temperature and taking into account radiative exchanges occurring inside an LPCVD reactor, with non-isothermal tube walls. This thermal model was incorporated in a global multiwafer model (CVD1), developed in our laboratory for prediction of the evolution of the longitudinal growth rate of polysilicon. Comparison between simulation results and experimental data led to the conclusion that the large drop-off in growth rate, at both ends of the reactor load, can be attributed to thermal variations within the reactor. This model can also be applied to the treatment of deposition processes involving temperature ramping, which are commonly used.