Patent ID: 6555166
Filing Date: 2003-04-29
Classification: C23C

Abstract:
A method for reducing the microloading effect in a chemical vapor deposition (CVD) process for depositing a film on a substrate in a CVD reactor, the CVD process using a gas mixture having at least one gaseous reactant and a carrier gas, the CVD process being characterized by a reactor chamber pressure, a deposition temperature and a film growth rate, the method comprising the steps of:identifying a growth-rate-limiting reactant, where the film growth rate varies in accordance with a concentration of said reactant in the CVD reactor; calculating a dilution factor, the dilution factor being a ratio of a gas flow of the growth-rate-limiting reactant to a total gas flow rate in the reactor; and adjusting at least one of the film growth rate and the dilution factor to satisfy a numerical criterion for reducing the microloading effect, said criterion being satisfied when the dilution factor is not less than a first quantity including as factors (a) the film growth rate and (b) a parameter characterizing variation of surface area of the substrate, wherein the process has a prescribed minimum film growth rate, and said adjusting is performed subject to the minimum film growth rate.