Formation method of porous insulating film, manufacturing apparatus of semiconductor device, manufacturing method of semiconductor device, and semiconductor device

A manufacturing method of a semiconductor device having at least one circuit element formed in a semiconductor substrate or a semiconductor layer and a multilayer interconnection structure formed on the semiconductor substrate or the semiconductor layer in a state in which the multilayer interconnection structure is electrically connected to the at least one circuit element, the semiconductor device having an multilayer interconnection formed by stacking plural unit interconnection structures each of which has an interconnection and a connecting plug formed by filling metal wiring in an interconnection trench and a via hole formed in an insulating film, comprising:

• supplying at least an organosiloxane and an inert gas to a reaction chamber, forming the insulating film by a plasma vapor deposition method, and varying a volume ratio of the organosiloxane and the inert gas to be supplied during deposition to change a partial pressure of the organosiloxane in the reaction chamber;
• and
• forming a lower adhesion layer of an interconnection interlayer dielectric in a process to excite plasma, forming the interconnection interlayer dielectric in a process to maintain the plasma, and forming an upper adhesion layer of the interconnection interlayer dielectric in a process to extinguish the plasma.

A semiconductor device having an insulating film formed by a plasma vapor deposition method with supplying at least a raw material of organosiloxane and an inert gas to a reaction chamber, wherein:

• the insulating film comprises a porous insulating film formed by a partial pressure control with varying a volume ratio of the raw material of organosiloxane and the inert gas during deposition, the porous film including a plurality of layers having different film characteristics wherein the porous insulating film comprises an insulating film and a film density near an interface of at least one of an upper layer and a lower layer of the insulating film is higher than that of an interior of the film and varies continuously.