Method of manufacturing semiconductor device

Abstract

A method of manufacturing a semiconductor device includes the steps of forming a plurality of gate electrodes, forming a first insulating film over the plurality of gate electrodes such that the first insulating film is embedded in a space between the plurality of gate electrodes, forming a second insulating film over the first insulating film, forming a third insulating film over the second insulating film, forming a photosensitive pattern over the third insulating film, performing etching using the photosensitive pattern as a mask to form a trench extending through the first to third insulating films and reaching a semiconductor substrate, removing the photosensitive pattern, performing etching using the exposed third insulating film as a mask to extend the trench in the semiconductor substrate, removing the third and second insulating films, and forming a fourth insulating film in the trench and over the first insulating film.

What is claimed is: 
     
         1 . A method of manufacturing a semiconductor device, comprising the steps of:
 forming a plurality of gate electrodes over a main surface of a semiconductor substrate;   forming a first insulating film over the gate electrodes such that the first insulating film is embedded in a space between the gate electrodes;   forming a second insulating film made of a material different from that of the first insulating film over the first insulating film;   forming a third insulating film made of a material different from that of the second insulating film over the second insulating film;   forming a photosensitive pattern over the third insulating film;   performing etching using the photosensitive pattern as a mask to form a trench extending through the first to third insulating films and reaching the semiconductor substrate;   removing the photosensitive pattern so as to expose the third insulating film;   performing etching using the exposed third insulating film as a mask to extend the trench into the semiconductor substrate;   removing the third and second insulating films; and   forming a fourth insulating film in the trench and over the first insulating film so as to form a hollow space in the trench.   
     
     
         2 . The method of manufacturing the semiconductor device according to  claim 1 ,
 wherein the third insulating film is formed so as to cover a bevel portion located in a peripheral edge of the main surface of the semiconductor substrate,   the method further comprising the step of:   after the formation of the third insulating film, forming a fifth insulating film made of a material different from that of the third insulating film so as to cover the third insulating film over the bevel portion,   wherein, with the fifth insulating film covering the third insulating film over the bevel portion, the trench is formed to extend through the first to third insulating films and reach the semiconductor substrate.   
     
     
         3 . The method of manufacturing the semiconductor device according to  claim 2 ,
 wherein the step of forming the fifth insulating film so as to cover the third insulating film over the bevel portion includes the steps of:   forming the fifth insulating film over the third insulating film; and   removing the fifth insulating film until the third insulating film is exposed to leave the fifth insulating film over the bevel portion.   
     
     
         4 . The method of manufacturing the semiconductor device according to  claim 1 , further comprising the step of:
 after the removal of the third and second insulating films, performing anisotropic dry etching on the first insulating film to remove the first insulating film from around the trench, while leaving the first insulating film located over side walls of the gate electrodes,   wherein, after the anisotropic dry etching of the first insulating film, the fourth insulating film is formed in the trench and over the first insulating film so as to form the hollow space in the trench.   
     
     
         5 . The method of manufacturing the semiconductor device according to  claim 4 ,
 wherein the step of performing the anisotropic dry etching on the first insulating film is performed until a position of an upper end of the first insulating film remaining over the side walls of the gate electrodes is located below upper ends of the gate electrodes.   
     
     
         6 . The method of manufacturing the semiconductor device according to  claim 1 , further comprising the step of:
 after the formation of the third insulating film, planarizing the third insulating film,   wherein, after the planarization of the third insulating film, the photosensitive pattern is formed over the third insulating film.   
     
     
         7 . A method of manufacturing a semiconductor device, comprising the steps of:
 forming a plurality of gate electrodes over a main surface of a semiconductor substrate;   forming a first insulating film over the gate electrodes such that the first insulating film is embedded in a space between the gate electrodes;   forming a second insulating film made of a material different from that of the first insulating film so as to cover the first insulating film over a bevel portion located in a peripheral edge of the main surface of the semiconductor substrate;   forming a photosensitive pattern over the first insulating film;   performing etching using the photosensitive pattern as a mask with the second insulating film covering the first insulating film over the bevel portion to form a trench extending through the first insulating film and reaching the semiconductor substrate;   removing the photosensitive pattern so as to expose the first insulating film;   performing etching using the exposed first insulating film as a mask to extend the trench into the semiconductor substrate; and   forming a third insulating film in the trench and over the first insulating film so as to form a hollow space in the trench.   
     
     
         8 . The method of manufacturing the semiconductor device according to  claim 7 ,
 wherein the step of forming the second insulating film so as to cover the first insulating film over the bevel portion includes the steps of:   forming the second insulating film over the first insulating film; and   removing the second insulating film until the first insulating film is exposed to leave the second insulating film over the bevel portion.   
     
     
         9 . The method of manufacturing the semiconductor device according to  claim 7 ,
 wherein the first insulating film includes a silicon dioxide film formed by causing an organic material to react in an atmosphere containing ozone and a silicon dioxide film formed by causing an organic material to react in a plasma.   
     
     
         10 . A method of manufacturing a semiconductor device, comprising the steps of:
 forming a plurality of gate electrodes over a main surface of a semiconductor substrate;   forming a first insulating film over the gate electrodes such that the first insulating film is embedded in a space between the gate electrodes;   forming a photosensitive pattern over the first insulating film;   performing etching using the photosensitive pattern as a mask to form a trench extending through the first insulating film into the semiconductor substrate;   removing the photosensitive pattern so as to expose the first insulating film; and   forming a second insulating film in the trench and over the first insulating film so as to form a hollow space in the trench.   
     
     
         11 . The method of manufacturing the semiconductor device according to  claim 10 ,
 wherein the first insulating film is formed so as to cover a bevel portion located in a peripheral edge of the main surface of the semiconductor substrate,   the method further comprising the step of:   after the formation of the first insulating film, forming a third insulating film made of a material different from that of the first insulating film so as to cover the first insulating film over the bevel portion,   wherein, with the third insulating film covering the first insulating film over the bevel portion, the trench extending through the first and third insulating films into the semiconductor substrate is formed.   
     
     
         12 . The method of manufacturing the semiconductor device according to  claim 11 ,
 wherein the step of forming the third insulating film so as to cover the first insulating film over the bevel portion includes the steps of:   forming the third insulating film over the first insulating film; and   removing the third insulating film until the first insulating film is exposed to leave the third insulating film over the bevel portion.   
     
     
         13 . The method of manufacturing the semiconductor device according to  claim 10 , further comprising the step of:
 after the formation of the first insulating film, planarizing the first insulating film,   wherein, after the planarization of the first insulating film, the photosensitive pattern is formed over the first insulating film.