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US 7,582,930 B2Granted
Non-volatile memory and method for manufacturing non-volatile memory
AssigneeNEC Electronics Corporation
InventorsAkira Yoshino, Yutaka Akiyama
Life of this patent
Estimating the term…
Abstract
A coupling oxide film is formed on a silicon substrate, a polysilicon film is further formed thereupon, and a low-temperature oxide film is deposited to a thickness of 10 nm, for example. Next, a silicon nitride film is formed on this low-temperature oxide film, and selectively removed by dry etching. At this time, the low-temperature oxide film serves as an etching stopper film, so the low-temperature oxide film and polysilicon film are not over-etched. Subsequently, the polysilicon film is dry-etched, forming a recess. A floating gate is then formed of the polysilicon film.
Claims20
A method for manufacturing non-volatile memory, comprising the steps of:
- forming a first insulating film on a first electroconductive semiconductor substrate;
- forming a first electroconductive film on said first insulating film;
- forming an etching stopper film on said first electroconductive film;
- forming a spacer film on said etching stopper film;
- selectively removing said spacer film by etching to said etching stopper film, so as to form an opening;
- removing said etching stopper film in said opening;
- forming a side wall insulating film on the side face of said opening;
- removing said first electroconductive film and said first insulating film within said opening;
- implanting impurities of a first electroconductivity type on the surface of said semiconductor substrate within said opening, thereby forming one of a source and drain;
- forming a floating gate of said first electroconductive film at the region directly below said side wall insulating film, by selectively etching away said first electroconductive film with said side wall insulating film as a mask;
- forming a second insulating film so as to cover the exposed face of said floating gate;
- forming a control gate;
- and
- forming the other of the source and drain by selectively implanting impurities of a second electroconductivity type on the surface of said semiconductor substrate, said side wall insulating film, said floating gate, and said control gate, as masks.
11 more elements
A non-volatile memory comprising:
- a first electroconductivity type semiconductor substrate with a mutually-distanced source and drain formed on the surface;
- a first insulating film provided in a region adjacent to one of said source and drain on the surface of said first electroconductivity type semiconductor substrate;
- a floating gate formed of a first electro conductive film provided on said first insulating film;
- a side wall insulating film provided on said second insulating film so as to cover part of said floating gate and allow the remainder thereof to protrude;
- a second insulating film for covering the protruding portion from said side wall insulating film of said floating gate;
- and
- a control gate formed of an electroconductive film and provided on said side wall insulating film;
- wherein said side wall insulating film, and said control gate, are provided in a region other than directly above the other of the source and drain,
- wherein the length of protrusion by which protruding portion protrudes from said side wall insulating film of said floating gate is 100 nm or less.
6 more elements
A method for manufacturing non-volatile memory with a floating gate, comprising:
- forming a first insulating layer on a semiconductor substrate;
- forming a first electroconductive film on said first insulating layer;
- forming a spacer film over said first electroconductive film;
- selectively removing said spacer film so as to form an opening;
- forming a second insulating layer on the surface of said spacer film and said opening;
- forming a third insulating layer on said second insulating layer;
- etching said second insulating layer and said third insulating layer sequentially, so as to form a first side wall insulating film of said second insulating layer and a second side wall insulating film of said third insulating layer on the side face of said opening;
- removing said first electroconductive film within said opening after said forming of said first side wall insulating film and said second side wall insulating film;
- removing said spacer film after said removing of said first electroconductive film within said opening;
- forming said floating gate of said first electroconductive film at the region directly below said first side wall insulating film and said second side wall insulating film, by selectively etching said first electroconductive film;
- and
- etching said first side wall insulating film, so as to expose the part on said floating gate.
9 more elements
Dependencies are inferred from the claim text.