US 5,493,146 AGranted

Anti-fuse structure for reducing contamination of the anti-fuse material

AssigneeVLSI Technology, Inc.

InventorsDipankar Pramanik, Subhash R. Nariani

Life of this patent

Estimating the term…

Loading patent…

Abstract

An anti-fuse structure formed in accordance with the present invention includes a conductive layer base. A layer of anti-fuse material overlies the conductive base layer. On top of the anti-fuse layer is an insulating layer, in which a via hole is formed to the anti-fuse layer. The lateral dimension of the via hole is less than about 0.8 microns. Provided in the via hole is a conductive non-Al plug including a conductive barrier material such as TiN or TiW to contact the anti-fuse material and overlie the insulating layer. Tungsten is effectively used as the non-Al plug. An electrically conductive layer is formed over the plug and is separaged from the anti-fuse layer by at least one-half the depth of the via hole. The structure is then programmable by application of a programming voltage and readable by application of a sensing voltage, which is lower than the programming voltage.

Claims22

Dependent claims

An anti-fuse structure comprising:

a conductive base layer;
a layer of anti-fuse material formed over said conductive base layer;
an insulating layer formed over said anti-fuse layer, said insulating layer being provided with a via hole to said anti-fuse layer, and said via hole having a lateral dimension no greater than about 0.8 microns and having a depth;
a conductive non-Al plug including a conductive barrier material chosen from the group consisting essentially of TiW, TiN, and chromium, provided within said via hole and in contact with said anti-fuse layer such that said anti-fuse structure may be programmed by providing a programming voltage between said conductive base layer and said conductive barrier material, and may be read by providing a sensing voltage, which is lower than said programming voltage, between said conductive base layer and said conductive barrier material;
and
an electrically conductive layer formed over and in electrical contact with said plug, said electrically conductive layer being separated from the anti-fuse layer by said plug by at least one-half said depth of the via hole.

3 more elements

Dependencies are inferred from the claim text.