Patent ID: 7504304
Filing Date: 2009-03-17
Classification: H01L

Abstract:
1. A process of manufacturing non-volatile semiconductor memory devices, comprising the steps of: forming device isolation trenches in a semiconductor substrate for defining device formation regions employed to form non-volatile semiconductor devices therein; forming a first device-isolation insulator film for electrically isolating said device formation regions from each other in said device isolation trenches with such a thickness that forms first recesses in said first device-isolation insulator film; forming a second device-isolation insulator film for electrically isolating said device formation regions from each other to fill said recesses; planarizing said first device-isolation insulator film and said second device-isolation insulator film; etching said first device-isolation insulator film and said second device-isolation insulator film on condition that said second device-isolation insulator film is higher in etching rate than said first device-isolation insulator film such that the uppermost portions at both ends of said first device-isolation insulator film are located higher than the uppermost portions at both ends of said second device-isolation insulator film to form second recesses; forming an upper gate insulator film on a surface of a floating gate material film and in said second recesses, said floating gate material film being formed on a lower gate insulator film above said device formation region; and forming a control gate material film on said upper gate insulator film.