US Patent 7566593 Fuse structure including cavity and methods for fabrication thereof

A fuse structure comprises a cavity interposed between a substrate and a fuse material layer. The cavity is not formed at a sidewall of the fuse material layer, or at a surface of the fuse material layer opposite the substrate. A void may be formed interposed between the substrate and the fuse material layer while using a self-aligned etching method, when the fuse material layer comprises lobed ends and a narrower middle region. The void is separated by a pair of sacrificial layer pedestals that support the fuse material layer. The void is encapsulated to form the cavity by using an encapsulating dielectric layer. Alternatively, a block mask may be used when forming the void interposed between the substrate and the fuse material layer.