Electrically programmable interlevel fusible link for integrated circuits

摘要

In a multi-level interconnect structure, a fusible material fills an opening in an isolation layer disposed between two interconnect levels or between an interconnect level and a device layer. The opening which may be, for example, a contact hole or a via, may be fabricated using processes generally used to fabricate normally sized vias and contact holes. The opening has a cross-sectional area A reduced by a factor of x relative to normally sized openings. Because the fusible interlevel interconnection has a reduced cross-sectional area, a programming current develops a destructive programming current density within fusible interlevel interconnection while current densities in coupled conductors, including normally sized vias and contacts, remain within long term reliability limits. Read/write circuitry connected to the fusible interlevel interconnection supports the programming current and supports a read current. The read current is regulated such that a responsive current density in a nonprogrammed fusible interlevel interconnection does not exceed long term reliability limits.