Back to results
US 6,656,793 B2Granted
Method of forming a self-aligned floating gate in flash memory cell
AssigneeHynix Semiconductor Inc.
InventorsCheol Mo Jeong, Pyeng Geun Sohn
Life of this patent
Estimating the term…
Abstract
A method of forming a self-aligned floating gate in a flash memory cell. A capping layer is formed on a trench insulating film. An etching process is then performed to etch the trench insulating film to a desired dimension. Therefore, generation of a moat in the trench insulating film is avoided. Further, spacing of a floating gate formed in a subsequent process can be minimized.
Claims18
A method of forming a self-aligned floating gate in a flash memory cell, the method comprising:
- forming a trench in a semiconductor substrate;
- forming a trench insulating film comprising a first protrusion in the trench, the first protrusion has a first width and a first height;
- forming a capping layer on the entire structure;
- forming a second smaller protrusion in the trench insulating film by etching the capping layer and a portion of the first protrusion, the second protrusion has a second width and a second height, the second width being narrower than the first width and the second height is less than the first height;
- and
- forming a floating gate isolated by the second protrusion of the trench insulating film.
3 more elements
A method of forming a self-aligned floating gate in a flash memory cell, the method comprising:
- forming a pad oxide film and a pad nitride on a semiconductor substrate;
- forming a trench in the semiconductor substrate by etching a portion of the semiconductor substrate, the pad nitride film and the pad oxide film;
- forming a sacrificial oxide film on an internal surface of the trench;
- removing the sacrificial oxide film;
- forming a wall oxide film on the internal surface of the trench;
- forming a liner oxide film on the entire structure;
- forming a trench insulating film on the liner oxide film;
- forming a first protrusion of the trench insulating film by performing a chemical mechanical polishing process and removing the pad nitride film, the first protrusion having a first width and a first height;
- forming a capping layer on the entire structure;
- forming a second protrusion of the trench insulating film by etching the capping layer and a portion of the first protrusion, the second protrusion having a second width and a second height, the second width being narrower than the first width and the second height being less than the first height;
- forming a tunnel oxide film and a floating gate isolated by the second protrusion of the trench insulating film;
- removing the second protrusion of trench insulating film;
- and
- forming a dielectric film and a control gate.
11 more elements
Dependencies are inferred from the claim text.