Patent ID: 7655577

Claim:
A method for forming a multi-layer silicon-containing insulation film on a substrate by plasma polymerization, comprising: introducing a reaction gas comprising (i) a source gas comprising a silicon-containing hydrocarbon cyclic compound having a silicon-containing ring and containing at least one vinyl group (Si-vinyl compound), and (ii) an additive gas, into a reaction chamber where a substrate is placed, wherein the Si-vinyl compound does not contain Si-O bonds in the silicon-containing ring, and the insulation film is a hard film composed of a silicon carbide material; and applying radio-frequency power to the gas to cause plasma polymerization, thereby depositing a multi-layer insulation film on the substrate, said radio-frequency power having a frequency of 2 MHz or higher without having a frequency of lower than 2 MHz, each layer having a dielectric constant of 3.0 or lower and a tensile stress of 60 MPa or lower.