Capacitive monitors for detecting metal extrusion during electromigration

A method for detecting metal extrusion associated with electromigration (EM) under high current density situations within an EM test line, the method comprising the steps of:

• situating one end of an electrically conductive lead close to a single anticipated location of metal extrusion associated with electromigration on the EM test line, such that the end of the electrically conductive lead in combination with the single anticipated location of metal extrusion together comprise two charge storing surfaces of a single capacitor having an electrical capacitance;
• situating one or more additional ends of one or more additional electrically conductive leads close to the single anticipated location of metal extrusion associated with electromigration on the EM test line, such that the end of each additional electrically conductive leads in combination with the single anticipated location of metal extrusion comprise charge storing surfaces of one or more additional capacitors each having an electrical capacitance;
• connecting the single capacitor and the one or more additional capacitors in parallel;
• measuring the capacitance of the single capacitor and the capacitances of the one or more additional capacitors prior to operation of the EM test line;
• making subsequent measurements of the capacitance of the single capacitor and the capacitances of the one or more additional capacitors during or after operation of the EM test line;
• and
• detecting changes in the capacitance of the single capacitor and the capacitances of the one or more additional capacitors to detect metal extrusion associated with electromigration.