Film formation method and apparatus for semiconductor process

A film formation method for a semiconductor process for forming an insulating film of boron doped silicon carbon nitride on a target substrate by CVD, in a process field configured to be selectively supplied with a silicon source gas, a nitriding gas, a boron-containing gas, and a carbon hydride gas, the method performing a plurality of cycles to laminate thin films respectively formed by the cycles, thereby forming the insulating film with a predetermined thickness, each of the cycles alternately comprising:

• an adsorption step of supplying the silicon source gas, the boron-containing gas, and the carbon hydride gas to the process field without supplying the nitriding gas to the process field, thereby forming an adsorption layer containing components derived from the gases supplied in the adsorption step on a surface of the target substrate;
• a first purge step of exhausting gas from the process field without supplying the silicon source gas, the nitriding gas, the boron-containing gas, and the carbon hydride gas to the process field;
• a nitridation step of supplying the nitriding gas to the process field without supplying the silicon source gas, the boron-containing gas, and the carbon hydride gas to the process field;
• and
• a second purge step of exhausting gas from the process field without supplying the silicon source gas, the boron-containing gas, the carbon hydride, and nitriding gases to the process field,
• wherein the adsorption step includes ,while continuously supplying the silicon source gas to the process field entirely through the adsorption step, a carbon supply period of supplying the carbon hydride gas to the process field without supplying the boron-containing gas to the process field, and a boron supply period of supplying the boron-containing gas to the process field without supplying the carbon hydride gas to the process field, in this order, in time series, so as to prevent the boron-containing gas and the carbon hydride gas from being simultaneously supplied to the process field.