Semiconductor integrated circuit device and process for manufacturing the same

Abstract

In the manufacture of a semiconductor device having a high-performance and high-reliability, a silicon nitride film 17 for self alignment, which film is formed to cover the gate electrode of a MISFET, is formed at a substrate temperature of 400° C. or greater by plasma CVD using a raw material gas including monosilane and nitrogen. A silicon nitride film 44 constituting a passivation film is formed at a substrate temperature of about 350° C. by plasma CVD using a raw material gas including monosilane, ammonia and nitrogen. The hydrogen content contained in the silicon nitride film 17 is smaller than that contained in the silicon nitride film 44 , making it possible to suppress hydrogen release from the silicon nitride film 17.

1 . A manufacturing process of a semiconductor device, comprising: 
 (a) selectively forming a first insulating film over a surface of a semiconductor substrate;    (b) forming a semiconductor layer in the semiconductor substrate in a region, in the surface of the semiconductor substrate, wherein the first insulating film does not exist;    (c) forming a refractory metal silicide layer over the surface of the semiconductor layer;    (d) forming a second insulating film to cover the refractory metal suicide layer and the first insulating film, the second insulating film providing self-alignment during self-alignment processing;    (e) forming a third insulating film over the second insulating film;    (f) forming an opening in the third and second insulating films; and    (g) forming a conductor piece in the opening,    wherein the second insulating film is a silicon nitride film formed by plasma CVD at 400° C. or greater, and    wherein the second insulating film is formed using a reaction gas having a silane and nitrogen gas in an ammonia-free atmosphere.    
   
   
       2 . A manufacturing process of a semiconductor device according to  claim 1 , wherein the second insulating film is formed using monosilane and nitrogen.  
   
   
       3 . A manufacturing process of a semiconductor device according to  claim 1 , wherein the third insulating film is a silicon oxide film, and wherein the opening forming step comprises a step of etching under conditions permitting a larger etching amount of the third insulating film relative to the second insulating film and a step of etching under conditions permitting a larger etching amount of the second insulating film relative to the first insulating film.  
   
   
       4 . A manufacturing process of a semiconductor device according to  claim 1 , wherein the silicide-layer forming step further comprises: 
 (h) depositing a refractory metal film over the semiconductor layer and first insulating film;    (i) heat treating the semiconductor substrate, thereby forming a silicide layer over a surface of the semiconductor layer; and    (j) removing the refractory metal film over the first insulating film.    
   
   
       5 . A manufacturing process of a semiconductor device according to  claim 1 , wherein the conductor piece contains a first conductor layer and a second conductor layer, and wherein the first conductor layer is thinner than the second conductor layer and lies below the second conductor layer.  
   
   
       6 . A manufacturing process of a semiconductor device according to  claim 5 , wherein the first conductor layer is a titanium nitride layer, while the second conductor layer is a tungsten layer.  
   
   
       7 . A manufacturing process of a semiconductor device according to  claim 1 , further comprising, between the steps (a) and (b), 
 forming a first conductor piece made of a silicon material, wherein a refractory metal silicide layer is formed on the surface of the first conductor piece in the step (c).    
   
   
       8 . A manufacturing process of a semiconductor device, comprising: 
 (a) selectively forming element isolation regions on a surface of a semiconductor substrate;    (b) forming a gate electrode over the surface of the semiconductor substrate via a gate insulating film;    (c) forming source and drain regions in the semiconductor substrate by introducing impurities;    (d) forming a first insulating film to cover the gate electrode, source and drain regions and element isolation regions, wherein the first insulating film provides self-alignment during self-alignment processing; and    (e) forming a second insulating film over the first insulating film,    wherein the first insulating film is formed by a plasma CVD method at a temperature of at least 400° C., using silane and nitrogen gas in an ammonia-free atmosphere.    
   
   
       9 . A manufacturing process of a semiconductor device according to  claim 8 , wherein the first insulating film is formed using monosilane and nitrogen.  
   
   
       10 . A manufacturing process of a semiconductor device according to  claim 8 , further comprising, between the steps (c) and (d): 
 (f) depositing a refractory metal film to cover at least the gate electrode, source region, and drain region;    (g) heat treating the semiconductor substrate, thereby forming a silicide layer over at least a surface of the gate electrode, and source and drain regions; and    (h) after the step (g), removing the remaining refractory metal film.    
   
   
       11 . A manufacturing process of a semiconductor device, comprising: 
 (a) forming a first insulating film over a semiconductor substrate, wherein the first insulating film provides self-alignment during self-alignment processing;    (b) forming a second insulating film over the first insulating film;    (c) forming an opening in the second and first insulating films; and    (d) forming a conductor layer in the opening,    wherein the first insulating film is a silicon nitride film formed by plasma CVD at a temperature of at least 400° C., using a silane and nitrogen gas in an ammonia-free atmosphere.    
   
   
       12 . A manufacturing process of a semiconductor device according to  claim 11 , wherein the silicon nitride film is formed using monosilane and nitrogen.  
   
   
       13 . A manufacturing process of a semiconductor device according to  claim 11 , wherein the second insulating film is a silicon oxide film.  
   
   
       14 . A manufacturing process of a semiconductor device according to  claim 11 , wherein the conductor-layer forming step comprises forming a first conductor layer as a lower layer and a second conductor layer as an upper layer, wherein the second conductor layer is made of copper, and wherein the first conductor layer serves to prevent diffusion of copper.  
   
   
       15 . A semiconductor device, comprising: 
 (a) a semiconductor substrate,    (b) a first insulating film selectively formed in the semiconductor substrate;    (c) a first conductor piece formed over the surface of the semiconductor substrate via a second insulating film,    (d) a semiconductor layer disposed between the first insulating film and first conductor piece in the semiconductor substrate;    (e) a third insulating film formed over the first conductor piece, first insulating film and semiconductor layer;    (f) a fourth insulating film formed over the third insulating film;    (g) a second conductor piece formed in the opening made in the third and fourth insulating films; and    (h) a fifth insulating film formed over the second conductor piece,    wherein the third and fifth insulating films are silicon nitride films formed by plasma CVD, and wherein the third insulating film has a hydrogen content smaller than that of the fifth insulating film.    
   
   
       16 . A semiconductor device according to  claim 15 , wherein the second conductor piece contains a first conductor layer and a second conductor layer, and wherein the first conductor layer is thinner than the second conductor layer and lies below the second conductor layer.  
   
   
       17 . A semiconductor device according to  claim 16 , wherein the first conductor layer is a titanium nitride layer, and wherein the second conductor layer is a tungsten layer.  
   
   
       18 . A semiconductor device according to  claim 15 , wherein a refractory metal silicide layer is formed over the surface of the semiconductor layer.  
   
   
       19 . A semiconductor device according to  claim 15 , wherein the first conductor piece is formed of a boron-containing silicon layer.  
   
   
       20 . A semiconductor device according to  claim 15 , wherein the first conductor piece is made of a silicon material, and wherein a refractory metal silicide layer has been formed over the surface of the first conductor piece.  
   
   
       21 . A semiconductor device comprising: 
 (a) a semiconductor substrate;    (b) a first conductor piece formed over the semiconductor substrate via a first insulating film;    (c) a second insulating film formed over the first conductor piece, and    (d) a third insulating film formed over the second insulating film, wherein the second and third insulating films are silicon nitride films formed by plasma CVD, and wherein the second insulating film has a hydrogen content smaller than that of the third insulating film.    
   
   
       22 . A semiconductor device according to  claim 21 , further comprising: 
 (e) first and second conductor regions disposed on opposite ends of the first conductor piece on the surface of the semiconductor substrate,    wherein the first conductor piece functions as a gate of a transistor, wherein the first and second semiconductor regions function as source and drain of the transistor, respectively, and wherein the second insulating film has a substantially equal width with the first conductor piece in a direction from the source toward the drain.    
   
   
       23 . A semiconductor device according to  claim 21 , further comprising: 
 (e) a second conductor piece formed over the second insulating film; and    (f) an externally connecting conductor piece connected to the second conductor piece,    wherein the third insulating film has an opening and in the opening, the externally connecting conductor piece is connected with the second conductor piece.    
   
   
       24 . A semiconductor device according to  claim 19 , further comprising: 
 (h) an externally connecting conductor piece connected with the second semiconductor piece,    wherein the fourth insulating film has a second opening, and wherein, in the second opening, the externally connecting conductor piece has been connected with the second conductor piece.    
   
   
       25 . A semiconductor device comprising: 
 (a) a semiconductor substrate;    (b) a first conductor piece formed via a first insulating film over the semiconductor substrate and having a side wall;    (c) a second insulating film formed over the side wall of the first conductor piece; and    (d) a third insulating film formed over the first conductor film,    wherein the second and third insulating films are silicon nitride films formed by plasma CVD, and wherein the second insulating film has a hydrogen content smaller than that of the third insulating film.    
   
   
       26 . A semiconductor device according to  claim 25 , further comprising: 
 (e) a second conductor piece formed over the second insulating film; and    (f) an externally connecting conductor piece connected with the second conductor piece,    wherein the third insulating film has an opening, and wherein, in the opening, the externally connecting conductor piece is connected with the second conductor piece.    
   
   
       27 . A semiconductor device comprising: 
 (a) a semiconductor substrate;    (b) a first insulating film over the semiconductor substrate;    (c) a second insulating film over the first insulating film,    (d) a first conductor piece formed in a first opening made in the first and second insulating films;    (e) a third insulating film over the first conductor piece,    (f) a second conductor piece over the third insulating film, and    (g) a fourth insulating film over the second conductor piece,    wherein the first and fourth insulating films are silicon nitride films formed by plasma CVD, and wherein the first insulating film has a hydrogen content smaller than that of the fourth insulating film.    
   
   
       28 . A semiconductor device, which comprises a first silicon nitride film for self alignment processing and a second silicon nitride film for passivation, wherein between an Si—H/Si—N bonds ratio R1 according to FT-IR analysis of the first silicon nitride film and an Si—H/Si—N bonds ratio R2 according to FT-IR analysis of the second silicon nitride film, there is a relationship of R1<R2.  
   
   
       29 . A semiconductor device according to  claim 28 , wherein the number of the Si—H bonds by the FT-IR analysis of the first silicon nitride film is 2×10 21  cm −3  or less.