Reactor transport effects in copper APCVD

Abstract

We have studied the chemical vapour deposition growth rates of copper films by H 2 reduction of Cu(hfac) 2 in a horizontal axial flow reactor, under reaction conditions that span the transition from transport-limited to reaction-limited growth. At high temperature and H 2 pressure (350 °C and 760 Torr), the growth rate becomes transport limited, resulting in highly non-uniform axial film thickness profiles. As the H 2 pressure is lowered to 40 Torr, the rate of convective and diffusive transport increases while the intrinsic rate decreases, leading to reaction-limited growth and more uniform films. At lower temperatures (250 °C), film growth is essentially reaction-limited at all H 2 pressures. We analyze the measured growth rate profiles using a reactor transport model to calculate the reactant concentration profiles and unmask the intrinsic growth rates. The results are used to optimize the kinetic parameter estimates for two recently proposed rate expressions for Cu(hfac) 2 reduction.