Semiconductor device and method of manufacturing the same

Abstract

An interlayer insulating film has via holes. A sidewall conductive layer is arranged along a sidewall surface of one via hole and contains one or more kinds selected from a group including tungsten, titanium, titanium nitride, tantalum and molybdenum. A second metal wiring layer is embedded in one via hole and contains aluminum. A plug layer is embedded in the other via hole and contains one or more kinds selected from the group including tungsten, titanium, titanium nitride, tantalum and molybdenum.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 a semiconductor substrate;   a first wiring layer which is formed over the semiconductor substrate;   an insulating film which covers the first wiring layer and has a first through-hole through which the first wiring layer is exposed;   a first conductive film which has a sidewall part disposed along a sidewall surface of the first through-hole, whose thickness is not more than ½ of a depth of the first through-hole on a bottom of the first through-hole and which does not extend over the insulating film; and   a second conductive film which is formed over the first conductive film, is embedded in the first through-hole and is made of aluminum.   
     
     
         2 . The semiconductor device according to  claim 1 ,
 wherein the first conductive film contains one or more kind(s) selected from a group including tungsten, titanium, titanium nitride, tantalum and molybdenum.   
     
     
         3 . The semiconductor device according to  claim 1 ,
 wherein the first wiring layer is exposed from the first conductive film on the bottom of the first through-hole.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein a first barrier metal layer is provided between the first wiring layer and the first conductive film.   
     
     
         5 . The semiconductor device according to  claim 1 ,
 wherein the second conductive film is provided between a sidewall surface of the first through-hole in the insulating film and the first conductive film.   
     
     
         6 . The semiconductor device according to  claim 1 ,
 wherein the insulating film is further provided with a second through-hole of a width which is smaller than a width of the first through-hole, and a third conductive film of a film thickness which is at least ½ of a depth of the second through-hole is provided in the second through-hole.   
     
     
         7 . The semiconductor device according to  claim 1 ,
 wherein a power element is disposed over the semiconductor substrate, and   wherein the first conductive film is electrically coupled to the power element.   
     
     
         8 . The semiconductor device according to  claim 6 ,
 wherein a MOS transistor is disposed over the semiconductor substrate, and   wherein the third conductive film is electrically coupled to the MOS transistor.   
     
     
         9 . A method of manufacturing semiconductor device comprising the steps of:
 (a) preparing a semiconductor substrate;   (b) forming a first wiring layer over the semiconductor substrate;   (c) forming an insulating film over the first wiring layer;   (d) forming a first through-hole through which the first wiring layer is exposed in the insulating film;   (e) forming a first conductive film which has a sidewall part disposed along a sidewall surface of the first through-hole, whose thickness is not more than ½ of a depth of the first through-hole on a bottom of the first through-hole and which does not extend over the insulating film; and   (f) forming a second conductive film which is embedded in the first through-hole and is made of aluminum over the first conductive film.   
     
     
         10 . The method of manufacturing semiconductor device according to  claim 9 , further comprising the steps of:
 (g) forming a second through-hole through which the first wiring layer is exposed in the insulating film; and   (h) forming a third conductive film of a film thickness which is at least ½ of a depth of the second through-hole in the second through-hole.   
     
     
         11 . The method of manufacturing semiconductor device according to  claim 10 ,
 wherein a coating conductive film which contains one or more kind (s) selected from a group including tungsten, titanium, titanium nitride, tantalum and molybdenum is formed along respective sidewall surfaces and bottom surfaces of the first through-hole and the second through-hole, the entire surface of the coating conductive film is etched back and thereby the first conductive film and the third conductive film are formed.   
     
     
         12 . The method of manufacturing semiconductor device according to  claim 11 ,
 wherein etching-back of the coating conductive film is performed until the bottom surface of the first through-hole is at least exposed from the coating conductive film.   
     
     
         13 . The method of manufacturing semiconductor device according to  claim 11 ,
 wherein etching-back of the coating conductive film is terminated before the bottom surface of the first through-hole is exposed from the coating conductive film.   
     
     
         14 . The method of manufacturing semiconductor device according to  claim 13 ,
 wherein etching-back of the coating conductive film is performed until a thickness of the thinnest part of the first conducive film reaches not more than ½ of a depth of the first through-hole.   
     
     
         15 . The method of manufacturing semiconductor device according to  claim 10 ,
 wherein the first through-hole and the second through-hole are formed such that a width of the first through-hole becomes larger than a width of the second through-hole.