Patent ID: 7446061

Claim:
A method of forming an insulating film to fill a gap formed in a processed substrate placed in a reaction chamber in which plasma is generated, the method comprising: introducing first process gases including an oxygen containing gas, a silicon containing gas and a hydrogen containing gas into the reaction chamber under a cluster formation condition set up with respect to a critical condition; and introducing second process gases including a silicon containing gas, and at least one of an oxygen containing gas and a hydrogen containing gas into the reaction chamber under a cluster suppression condition set up with respect to the critical condition, wherein a ratio of a gas flow of the hydrogen containing gas except the silicon containing gas to a total gas flow of the silicon containing gas and the oxygen containing gas defines a first gas-flow ratio, a ratio of a gas flow of the oxygen containing gas to that of the silicon containing gas defines a second gas-flow ratio, the critical condition is a linear function defined by the first and second gas-flow ratios, the cluster formation condition is set by gas flows which relatively increase the first gas-flow ratio but relatively decrease the second gas-flow ratio, and the cluster suppression condition is set by gas flows which relatively decrease the first gas-flow ratio but relatively increase the second gas-flow ratio.