Method for manufacturing a semiconductor device

Abstract

The performances of a semiconductor device are improved. In a method for manufacturing a semiconductor device, in a memory cell region, a control gate electrode formed of a first conductive film is formed over the main surface of a semiconductor substrate. Then, an insulation film and a second conductive film are formed in such a manner as to cover the control gate electrode, and the second conductive film is etched back. As a result, the second conductive film is left over the sidewall of the control gate electrode via the insulation film, thereby to form a memory gate electrode. Then, in a peripheral circuit region, a p type well is formed in the main surface of the semiconductor substrate. A third conductive film is formed over the p type well. Then, a gate electrode formed of the third conductive film is formed.

1 - 13 . (canceled) 
     
     
         14 . A method for manufacturing a semiconductor device, comprising:
 (a) providing a semiconductor substrate;   (b) forming an element isolation region in the semiconductor substrate such that first and second regions of a first main surface of the semiconductor substrate are defined by the element isolation region;   (c) forming a first insulation film over the first region of the first main surface of the semiconductor substrate, the first insulation film including a first silicon oxide film, a first silicon nitride film over the first silicon oxide film, and a second silicon oxide film over the first silicon nitride film;   (d) forming a first conductive film over the first insulation film;   (e) patterning the first conductive film to form a first gate electrode from a portion of the first conductive film, and forming a first gate insulation film from a portion of the first insulation film between the first gate electrode and the semiconductor substrate;   (f) after the step (e), forming a well of a first conductivity type within the semiconductor substrate in the second region;   (g) after the step (f), forming a second insulation film over the second region of the first main surface of the semiconductor substrate;   (h) forming a second conductive film over the second insulation film; and   (i) patterning the second conductive film to form a second gate electrode from a portion of the second conductive film, and forming a second gate insulation film from a portion of the second insulation film between the second gate electrode and the semiconductor substrate.   
     
     
         15 . The method for manufacturing a semiconductor device according to  claim 14 ,
 wherein, in the step (c), the first silicon oxide film is formed using a ISSG oxidation method.   
     
     
         16 . The method for manufacturing a semiconductor device according to  claim 14 ,
 wherein, in the step (c), the first silicon oxide film is formed using a thermal oxidation method.   
     
     
         17 . The method for manufacturing a semiconductor device according to  claim 16 , comprising:
 (j) after the step (b) and before the step (c), forming a well of a second conductivity type within the semiconductor substrate in the first region.   
     
     
         18 . The method for manufacturing a semiconductor device according to  claim 17 , comprising:
 (k) after the step (e) and before the step (f), forming a third insulation film over the first gate insulation film, the first gate electrode, and the first main surface in the first region so as to cover the first region.   
     
     
         19 . The method for manufacturing a semiconductor device according to  claim 18 ,
 wherein, in the step (k), the third insulation film includes a third silicon oxide film and a second silicon nitride film over the third silicon oxide film.   
     
     
         20 . The method for manufacturing a semiconductor device according to  claim 19 ,
 wherein, in the step (h), the second conductive film is formed over the third insulation film in the first region.   
     
     
         21 . The method for manufacturing a semiconductor device according to  claim 17 ,
 wherein, the first region is a memory cell region, and,   wherein, the second region is a peripheral circuit region.