Semiconductor device having a interlayer insulation film with low dielectric constant and high mechanical strength

Abstract

A method for fabricating a semiconductor includes the steps of forming a porous insulation film and wires on a substrate, the wires embedded in the porous insulation film having a portion adjacent to the wires and a remote portion spaced apart from the wires; and applying an energy beam to the remote portion to change the structure of the porous insulation film such that an Young's modulus of the porous insulation film increased so as to substantially reinforce the strength of the porous insulation film.

1 . A method for fabricating a semiconductor device comprising the steps of:
 forming a porous insulation film and a plurality of wires on the substrate, the wires embedded in the porous insulation film having a portion adjacent to the wires and a remote portion spaced apart from the wires; and   applying an energy beam to the remote portion to change the structure of the porous insulation film such that an Young's modulus of the porous insulation film increased so as to substantially reinforce the strength of the porous insulation film.   
   
   
       2 . The method for fabricating the semiconductor device according to  claim 1 , wherein
 the wires are made of a metal, and   the porous insulation film is made of a silicon oxide film.   
   
   
       3 . The method for fabricating the semiconductor device according to  claim 1 , wherein the porous insulation film is formed from a starting material containing silicon, oxygen, and hydrogen. 
   
   
       4 . The method for fabricating the semiconductor device according to  claim 1 , wherein a plurality of wiring layers are stacked, each wiring layer including the porous insulation film and the wires, and the portion includes the wires arranged at a minimum pitch. 
   
   
       5 . The method for fabricating the semiconductor device according to  claim 4 , wherein the portion corresponds to a form obtained by extending the periphery of the minimum-pitched wiring area by a predetermined distance. 
   
   
       6 . The method for fabricating the semiconductor device according to  claim 1 , wherein a plurality of wiring layers are stacked, each wiring layer including the porous insulation film and the wires, and the portion having a form obtained by extending by a predetermined distance in the width direction of a wire of the wires from the center of the wire with respect to all wires. 
   
   
       7 . The method for fabricating the semiconductor device according to  claim 6 , wherein the predetermined distance is a half of the minimum pitch. 
   
   
       8 . The method for fabricating the semiconductor device according to  claim 1 , wherein the energy beam is an electron beam. 
   
   
       9 . The method for fabricating the semiconductor device according to  claim 1 , wherein the energy beam is ultraviolet light. 
   
   
       10 . The method for fabricating the semiconductor device according to  claim 1 , wherein heat treatment is performed while applying the energy beam. 
   
   
       11 . The method for fabricating the semiconductor device according to  claim 1 , wherein the step of forming the porous insulation film includes the steps of:
 applying an insulation film material containing a thermally decomposable compound on the substrate by spin-coating; and   performing heat treatment so that the thermally decomposable compound is decomposed and pores are formed in the insulation film material.   
   
   
       12 . The method for fabricating the semiconductor device according to  claim 1 , wherein the step of forming the porous insulation film includes the steps of:
 applying an insulation film material containing a cluster compound; and   performing heat treatment so that a solvent in the insulation film material is vaporized and pores are formed in the insulation film material.