Electromigration

Electromigration is a phenomenon observed in integrated circuits, where high-density electric current can cause the transport of material within the conductor. This can lead to the formation of voids and hillocks in the conductor, which can ultimately lead to circuit failure.

Overview

Electromigration is a result of the momentum transfer between conducting electrons and the metal ions that make up the lattice of the conductor. The momentum transfer causes the metal ions to move in the direction of electron flow, which can lead to the formation of voids and hillocks. This phenomenon is particularly problematic in microelectronics, where the high current densities can lead to rapid electromigration damage.

Mechanism

The mechanism of electromigration involves several steps. First, the momentum of the conducting electrons is transferred to the metal ions in the lattice of the conductor. This causes the ions to move in the direction of electron flow. Over time, this can lead to the formation of voids in the conductor, which can interrupt the flow of current. In addition, the movement of ions can cause the formation of hillocks, which can lead to short circuits.

Factors Influencing Electromigration

Several factors can influence the rate of electromigration, including the current density, the conductor material, the temperature, and the structure of the conductor. Higher current densities and temperatures can increase the rate of electromigration, while certain materials and structures can be more resistant to electromigration damage.

Prevention and Mitigation

There are several strategies for preventing and mitigating electromigration damage. These include using materials that are more resistant to electromigration, designing circuits to operate at lower current densities, and using cooling techniques to reduce the temperature of the conductor.

See Also

• Integrated circuit
• Electric current
• Microelectronics