Patent ID: 7645481

Claim:
A method of forming a low-k insulating film, comprising the steps of: placing a substrate, on which an insulating film formed of a silicon alkoxide series material containing CH 3 —Si—O bonds has been deposited by a chemical vapor deposition process, in a reaction vessel; supplying a process gas containing hydrogen atoms into the reaction vessel and supplying a microwave into the reaction vessel, thereby generating a plasma containing hydrogen radicals; and modifying a structure of the insulating film deposited on the substrate by means of the hydrogen radicals contained in the plasma, thereby lowering a dielectric constant of the insulating film, wherein in the supplying step, as the process gas, hydrogen gas and argon gas are supplied into the reaction vessel with an argon/hydrogen ratio ranging from 1000/100 to 100/1000, and the step of lowering the dielectric constant of the insulating film includes a step of increasing an interatomic distance of Si—O bonds in the CH 3 —Si—O bonds.