Interconnects between components and layers of chips can

be damaged by excessive heating when a pulse of current from an electrostatic discharge passes through them. Aluminum interconnects are sandwiched between thin layers of titanium, which adhere better to the adjoining insulator. When the wire heats up, insulator on each side cracks and molten aluminum oozes out, as shown here for a silicon-on-insulator microprocessor that was subjected to a 7,500-volt discharge (a). More modern copper wiring has a higher melting point. The copper is in a trough of tantalum. The layer of insulator above the copper cracks when the wire is heated (b). When there is no insulator on top, the copper blisters or vaporizes (c). At extremely high temperatures (3,017 degrees Celsius and up), the tantalum sidewalls melt, allowing copper to extrude (d). (Numbers indicate wire widths in microns.)

Comments