Semiconductor device and method of manufacturing the same
AssigneeNEC Corporation
InventorsMunehiro Tada, Toshitsugu Sakamoto, Hiromitsu Hada, Naoki Banno
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Abstract
A semiconductor device comprises a semiconductor substrate; a multilevel wiring layer structure on the semiconductor substrate; and a variable resistance element in the multilevel wiring layer structure, wherein the variable resistance element comprises a variable resistance element film whose resistance changes between a top electrode and a bottom electrode, wherein the multilevel wiring layer structure comprises at least a wiring electrically connected to the bottom electrode and a plug electrically connected to the top electrode, and wherein the wiring also serves as the bottom electrode.
Claims12
A method of manufacturing a semiconductor device comprising a variable resistance element in a multilevel wiring layer structure on a semiconductor substrate,
- wherein the variable resistance element comprises a variable resistance element film disposed between a top electrode and a bottom electrode;
- wherein the multilevel wiring layer structure comprises at least a wiring electrically connected to the bottom electrode and a plug electrically connected to the top electrode;
- wherein the wiring is made of a metal and also serves as the bottom electrode;
- wherein the variable resistance element film is a film whose resistance changes depending on ion conduction or diffusion of the metal of the wiring;
- and
- wherein an insulating barrier film is in contact with the bottom electrode and the variable resistance element film in a portion arranged between the bottom electrode and the variable resistance element film;
- the method comprising:
- forming the insulating barrier film having an opening extending to the bottom electrode on the bottom electrode;
- forming the variable resistance element film and the top electrode in this order on the insulating barrier film and the bottom electrode exposed in the opening;
- and
- forming the plug on the top electrode,
- wherein the forming the variable resistance element film comprises:
- forming the insulating barrier film on the bottom electrode;
- forming a hard mask having an opening pattern on the insulating barrier film;
- using the hard mask as a mask and carrying out reactive dry etching on the insulating barrier film exposed in the opening pattern to form the opening in the insulating barrier film, the opening extending to the bottom electrode, having a tapered wall surface, and having a wider diameter at a portion farther from the bottom electrode;
- and
- using an inactive gas and carrying RF etching to adjust the tapered surface of the opening to a desired angle, and
- wherein, in the forming the variable resistance element film and the top electrode, the variable resistance element film is formed also on the tapered surface.
Dependencies are inferred from the claim text.