Nonvolatile semiconductor memory device and method for manufacturing the same
AssigneeKabushiki Kaisha Toshiba
InventorTatsuhiro Oda
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Abstract
According to one embodiment, a nonvolatile semiconductor memory device includes a silicon-containing substrate, a plurality of memory cells, and an insulating film. The substrate includes silicon. The plurality of memory cells is provided on the substrate with a spacing therebetween. The insulating film is provided on a sidewall of the memory cell. The insulating film includes a protrusion protruding toward an adjacent one of the memory cells above a void portion is provided between the memory cells.
Claims18
A nonvolatile semiconductor memory device comprising:
- a silicon-containing substrate;
- a plurality of memory cells provided on the substrate with a spacing therebetween;
- and
- an insulating film including a first silicon oxide film and a second silicon oxide film,
- the first silicon oxide film provided on a sidewall of the memory cell, and on a surface of the silicon-containing substrate between the memory cells,
- the second silicon oxide film provided on the first silicon oxide film above a void portion provided between the memory cells, the second silicon oxide film including a protrusion protruding toward an adjacent one of the memory cells, a material of the second silicon oxide film being same as a material of the first silicon oxide film;
- the memory cells including:
- a tunnel insulating film provided on the substrate;
- a floating gate provided on the tunnel insulating film;
- an intergate insulating film provided on the floating gate;
- and
- a control gate provided on the intergate insulating film;
- the protrusion is provided above an upper surface of the floating gate;
- and
- a height of an upper end of the protrusion is lower than a height of an upper end of the control gate.
A method for manufacturing a nonvolatile semiconductor memory device, comprising:
- forming a film constituting a tunnel insulating film on the silicon-containing substrate;
- forming a film constituting a floating gate on the film constituting the tunnel insulating film;
- forming a film constituting an intergate insulating film on the film constituting the floating gate;
- forming a film constituting a control gate on the film constituting the intergate insulating film;
- forming an etching mask on the film constituting the control gate;
- forming a plurality of memory cells on the silicon-containing substrate with a spacing therebetween by performing etching processing;
- forming a first silicon oxide film on a sidewall of the memory cell, and on a surface of the silicon-containing substrate between the memory cells;
- forming a sacrificial film between the memory cells, the sacrificial film being made of a material having a higher etching rate than the first silicon oxide film;
- forming a second silicon oxide film on the first silicon oxide film and an upper surface of the sacrificial film, a material of the second silicon oxide film being same as a material of the first silicon oxide film;
- forming a protrusion protruding toward an adjacent one of the memory cells by removing part of the second silicon oxide film formed on the upper surface of the sacrificial film, the protrusion formed by stacking the second silicon oxide film on the first silicon oxide film and a height of an upper end of the protrusion being lower than a height of an upper end of the control gate;
- and
- removing the sacrificial film.
Dependencies are inferred from the claim text.