Semiconductor device and a method of manufacturing the same

摘要

A method of manufacturing a semiconductor device having a non-volatile memory cell includes forming first insulating films with first conductive films arranged therebetween, recessing the first insulating films using the first conductive films as a mask, so that heights of top surfaces of the first insulating films are lower than heights of top surfaces of the first conductive films, forming a second insulating film over the first conductive and insulating films, forming a second conductive film over the second insulating film, and patterning the first and second conductive films, and the second insulating film. A length of the floating gate in a second direction is larger than a maximum length of the floating gate in a first direction, and a length from a top surface of the second insulating film to a top surface of the floating gate is larger than a length of a space between a plurality the floating gates.

主权项

1. A method of manufacturing a semiconductor device having a non-volatile memory cell including a word line extending to a first direction and a plurality of floating gates, comprising the steps of:
(a) forming a plurality of first insulating films and a plurality of first conductive films arranged between each of the first insulating films over semiconductor substrate, wherein the first insulating films and the first conductive films extend in a second direction being perpendicular to the first direction, and wherein the first insulating films cover sidewalls of the first conductive films, respectively; (b) after the step (a), recessing the first insulating films by using the first conductive films as a mask, thereby a height of a top surface of the first insulating film is lower than a height of a top surface of the first conductive film, such that the first insulating films respectively cover lower sidewall portions of the first conductive films and upper sidewall portions of the first conductive films are exposed; (c) after the step (b), forming a second insulating film over the first conductive films and the first insulating films, such that the exposed upper sidewall portions of the first conductive films and upper surfaces of the first insulating films covering the lower sidewall portions of the first conductive films are covered by the second insulating film; (d) after the step (c), forming a second conductive film over the second insulating film; and (e) after the step (d), patterning the second conductive film, the second insulating film and the first conductive films, respectively, wherein, by the step (e), the word line including the second conductive film is formed, and the floating gates including the first conductive films are formed, wherein, after the step (e), a length of the floating gates in the second direction is larger than a maximum length of the floating gates in the first direction, and wherein a protrusion height of the floating gates, which are covered by the second insulating film, from a top surface of a portion of the second insulating film which is formed over the top surface of first insulating films, covering the lower sidewall portions of the first conductive films forming the floating gates, to a top surface of the floating gates is larger than a length of a space between the each of the floating gates in the first direction.