Low-permittivity porous siliceous film, semiconductor devices having such films, and coating composition for forming the film

Abstract

A porous silica coating having a dielectric constant of less than 2.5, a semiconductor device comprising the porous silica coating formed therein, and a coating composition for forming the porous silica coating. The coating composition is composed of an aluminum-containing polysilazane and a polyacrylate or polymethacrylate ester in an organic solvent. The coating composition is coated and then fired, thereby to obtain a porous silica coating. The porous silica coating can be used as an interlayer dielectric by forming on a semiconductor device.

1 . A porous silica coating having a dielectric constant of less than 2.5, which is obtained by firing a coating of a composition comprising an aluminum-containing polysilazane and a polyacrylate or polymethacrylate ester.  
     
     
         2 . The porous silica coating according to  claim 1 , which maintains a dielectric constant of less than 2.5 even after being left to stand in an atmospheric air at a temperature of 23° C. and a relative humidity of 50% for a week.  
     
     
         3 . The porous silica coating according to  claim 1  or  2 , wherein the dielectric constant is 2.1 or less.  
     
     
         4 . The porous silica coating according to  claim 1 , which has a pore diameter within a range from 0.5 to 30 nm.  
     
     
         5 . The porous silica coating according to  claim 1 , wherein the polysilazane in the aluminum-containing polysilazane has a silazane structure represented by the following general formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and R 3  each independently represents a hydrogen atom, a hydrocarbon group, a hydrocarbon group-containing silyl group, a hydrocarbon group-containing amino group, or a hydrocarbonoxy group, provided that at least one of R 1  and R 2  represents a hydrogen atom.  
     
     
         6 . The porous silica coating according to  claim 5 , wherein the content of Si, which exists in the form of a Si—R 1  or Si—R 2  bond, is within a range from 10 to 100 atomic % based on the number of Si atoms contained in the silica porous coating.  
     
     
         7 . The porous silica coating according to  claim 6 , wherein all of R 1 , R 2  and R 3  are hydrogen atoms.  
     
     
         8 . The porous silica coating according to  claim 6  or  7 , which is substantially free from a Si—N bond.  
     
     
         9 . A semiconductor device comprising the porous silica coating of  claim 1  as an interlayer dielectric.  
     
     
         10 . (deleted)