Method of forming conductive layers in the trenches or through holes made in an insulating film on a semiconductor substrate

Abstract

Conductive layers are formed in the trenches made in an insulating film in the following manner. First, an amorphous silicon film 26 A is deposited in the trenches 25 made in a silicon oxide film 24. A photoresist film 30 is then formed on the amorphous silicon film 26 A by means of spin coating. Then, exposure light is applied to the entire surface of the photoresist film 30, thereby exposing to light those parts of the photoresist film 30 which lie outside the trenches 25. The other parts of the photoresist film 30, which lie in the trenches 25 are not exposed to light because the light reaching them is inadequate. Further, the photoresist film 30 is developed thereby removing those parts of the film 30 which lie outside the trenches 25 and which have been exposed to light. Thereafter, those parts of the amorphous silicon film 26 A, which lie outside the trenches 25, are removed by means of dry etching using, as a mask, the unexposed parts of the photoresist film 30 which remain in the trenches 25.

What is claimed is:  
     
         1 . A method of manufacturing a semiconductor integrated circuit device, comprising the steps of: 
 (a) forming a first conductive film on a major surface of a semiconductor substrate, forming a first insulating film on the first conductive film, and making a trench or a through hole in the first insulating film;    (b) forming a second conductive film in the trench or the through hole and on the first insulating film, said second conductive film extending through the trench or the though hole and electrically connected to the first conductive film;    (c) covering the second conductive film with a photoresist film and applying exposure light to the photoresist film, thereby exposing to light at least that part of the photoresist film which lies outside the trench or the though hole;    (d) removing that part of the photoresist film which is exposed to light, thus leaving the other, unexposed part of the photoresist film in the trench or the through hole; and    (e) removing that part of the second conductive film which is not covered with the photoresist film, thereby leaving the other part of the second conductive film in the trench or the through hole.    
     
     
         2 . The method of manufacturing a semiconductor integrated circuit device according to  claim 1 , wherein the second conductive film is removed in part in the step (e) etching method.  
     
     
         3 . The method of manufacturing a semiconductor integrated circuit device according to  claim 1 , wherein the second conductive film is removed in part in the step (e) by chemical mechanical polishing method.  
     
     
         4 . The method of manufacturing a semiconductor integrated circuit device according to  claim 1 , wherein the photoresist film is removed in part in the step (d) by developing the photoresist film.  
     
     
         5 . The method of manufacturing a semiconductor integrated circuit device according to  claim 1 , after the step (e) has been performed, further comprising a step (f) of removing that part of the photoresist film lying in the trench or the through hole and selectively growing a third conductive film on the second conductive film exposed in the trench or the through hole, thereby burying the third conductive film in the trench or the through hole.  
     
     
         6 . The method of manufacturing a semiconductor integrated circuit device according to  claim 5 , wherein the second conductive film is made of titanium nitride or tungsten.  
     
     
         7 . The method of manufacturing a semiconductor integrated circuit device according to  claim 5 , wherein the third conductive film is made of tungsten or aluminum alloy.  
     
     
         8 . The method of manufacturing a semiconductor integrated circuit device according to  claim 5 , after a step (f) has been performed, further comprising the step (h) of forming a fourth conductive film on the first insulating film and electrically connecting the fourth conductive film to the first conductive film via the third conductive film in the trench or the through hole.  
     
     
         9 . The method of manufacturing a semiconductor integrated circuit device according to  claim 1 , further comprising the following steps (f) and (g) which are performed after the step (e); 
 (f) removing that part of the photoresist film which lie in the trench or the through hole, and forming a fifth conductive film in the trench or the through hole and on the first insulating film; and    (g) growing a sixth conductive film on the fifth conductive film and removing those parts of the sixth and fifth conductive films which lie outside the trench or the through hole, thereby leaving the sixth and fifth conductive films in the trench or the through hole.    
     
     
         10 . The method of manufacturing a semiconductor integrated circuit device according to  claim 9 , wherein the second conductive film is made of titanium nitride or tantalum nitride.  
     
     
         11 . The method of manufacturing a semiconductor integrated circuit device according to  claim 9 , wherein the fifth and sixth conductive films are made of copper.  
     
     
         12 . The method of manufacturing a semiconductor integrated circuit device according to  claim 9 , wherein said parts of the sixth and fifth conductive films are removed by chemical mechanical polishing method.