Monitoring copper corrosion in an integrated circuit device

Abstract

Systems and methods for monitoring copper corrosion in an integrated circuit (IC) device are disclosed. A corrosion-sensitive structure formed in the IC device may include a p-type active region adjacent an n-type active region to define a p-n junction space charge region. A copper region formed over the silicon may be connected to both the p-region and n-region by respective contacts, to thereby define a short circuit. Light incident on the p-n junction space charge region, e.g., during a CMP process, creates a current flow through the metal region via the short circuit, which drives chemical reactions that cause corrosion in the copper region. Due to the short circuit configuration, the copper region is highly sensitive to corrosion. The corrosion-sensitive structure may be arranged with less corrosion-sensitive copper structures in the IC device, with the corrosion-sensitive structure used as a proxy to monitor for copper corrosion in the IC device.