Fabrication of low dielectric constant insulating film

Abstract

The present invention relates to a method of lowering dielectric constant of an insulating film including Si, O and CH formed by a chemical vapor deposition process. A process gas containing hydrogen atoms is supplied into a reaction vessel. A microwave is introduced into the reaction vessel to supply a uniform electromagnetic wave, thereby a plasma containing a hydrogen radical is generated in the reaction vessel. The structure of the insulating film is modified by the hydrogen radical contained in the plasma irradiated to the insulating film, lowering the dielectric constant of the film. The microwave is supplied into the reaction vessel through a radial-slot antenna.

1 - 13 . (canceled) 
   
   
       14 . A plasma processing system comprising:
 a reaction vessel;   a pedestal arranged on the reaction vessel to place a substrate thereon;   a heater adapted to heat the substrate placed on the pedestal;   a microwave supplying apparatus that supplies a microwave into the reaction vessel;   a gas supplying apparatus that supplies hydrogen gas and argon gas into the reaction vessel;   an exhaust apparatus that evacuates the reaction vessel to regulate pressure in the reaction vessel; and   a controller that controls the gas supplying apparatus to supply hydrogen gas and argon gas into the reaction vessel while an argon/hydrogen ratio is set in a range of 1000/100 to 100/1000 when the substrate on which an insulating film formed of a silicon alkoxide series material containing CH 3 —Si—O bonds is placed on the pedestal, and controls the microwave supplying apparatus to supply the microwave into the reaction vessel to generate a plasma containing hydrogen radicals to increase an interatomic distance of Si—O bonds in the CH 3 —Si—O bonds and to lower a dielectric constant of the insulating film.   
   
   
       15 . The plasma processing system according to  claim 14 , wherein the controller controls the pressure in the reaction vessel within a range of 0.5 to 5 Torr by the exhaust apparatus, when the hydrogen gas, the argon gas and the microwave are supplied into the reaction vessel. 
   
   
       16 . The plasma processing system according to  claim 14 , further comprising:
 a radial slot antenna of a circular-disc shape having a plurality of slits formed therein, the radial slot antenna receiving the microwave supplied by the microwave supplying apparatus and emitting the microwave via the plurality of slits; and   a dielectric plate that allows the microwave emitted from the slits of the radial slot antenna to be transmitted through the dielectric plate to introduce the microwave into the reaction chamber, wherein   a lower surface of the dielectric plate faces the substrate placed on the pedestal, and   the dielectric plate and the pedestal are dimensioned and disposed such that a gap size between the lower surface of the dielectric plate and the substrate placed on the pedestal is within a range of 30 to 143 mm.   
   
   
       17 . A storage medium storing a software executable by a control computer of a plasma processing system, wherein, upon execution of the software, the control computer controls the plasma processing system to make the system perform a plasma processing method that reduces a dielectric constant of an insulating film formed on a substrate, said plasma processing method including:
 placing the substrate 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 increasing an interatomic distance of Si—O bonds in the CH 3 —Si—O bonds and lowering the dielectric constant of the insulating film, wherein   the substrate on which the insulating film is formed of a silicon alkoxide series material containing CH 3 —Si—O bonds is deposited by a chemical vapor deposition process, and   the process gas supplied into the reaction vessel in the supplying step has an argon/hydrogen ratio of 1000/100 to 100/1000.