What are the effects of electromigration?
The electromigration (EM) effect describes atomic diffusion in conductors driven by electric currents, which may lead to the formation of voids and hillocks at the cathode and the anode, respectively1.
What is electromigration reliability?
Electromigration reliability of a wire (Black’s equation) For an interconnect of a given construction to remain reliable as the temperature rises, the current density within the conductor must be reduced.
How do you mitigate electromigration?
Fortunately, there are well-known ways to reduce current density and mitigate electromigration….They are:
- Widen the wire to reduce current density.
- Reduce the frequency.
- Lower the supply voltage.
- Keep the wire length short.
- Reduce buffer size in clock lines.
What causes electromigration?
Electromigration is the movement of atoms based on the flow of current through a material. If the current density is high enough, the heat dissipated within the material will repeatedly break atoms from the structure and move them.
What is electromigration analysis?
Electromigration (EM) analysis in VLSI design refers to optimizing IC interconnects to prevent electrochemical growth. The processes governing EM in a PCB is different from what occurs in an IC, and the solutions used in each domain are different. VLSI optimization requires balancing signal speed with current density.
What is activation energy in electromigration?
The electromigration (EM) activation energy (E A ) of alternative metals, such as Ru and Co, was obtained using low-frequency noise (LFN) measurements. High activation energies were expected, but values of ≈1 eV are found, most likely related to diffusion along with the metal-dielectric interface.
What is the effect of temperature on electromigration?
Through the experiments, we demonstrate that EM damage can be prevented much more by decreasing temperature and the increase of the passivation hardness with decreasing temperature is assumed to have an influence on the ability of passivation to prevent EM damage.
What is electromigration layout?
Electromigration is a failure mechanism that needs to be considered in VLSI physical design. Inside an integrated circuit, atoms in traces that make up interconnects can experience diffusion, where they are transported along the direction of the voltage drop and settle into hillocks on the edge of the conductor.
How is electromigration measured?
Electromigration is measured by subjecting the conductor to the high current density, detecting failure (often defined as 50% reduction in cross-section area) and evaluating many samples prepared in the same way.
What is electromigration for conduction wires within chips?
Electromigration damage. Electromigration is the mass transport in a metallic conductor due to the momentum transfer between conducting electrons and diffusing metal atoms.
Does electromigration occur at grain boundaries in aluminum?
In aluminum, very little electromigration occurred at grain boundaries, and so migration was largely independent of microstructure.
What is the difference between aluminum and copper interconnect wiring?
The replacement of aluminum with copper interconnect wiring, first demonstrated by IBM in 1997, brought the integrated circuit industry substantial improvements in both resistance to electromigration and line conductivity. Copper is both a better and more stable conductor than aluminum.
Do large grains reduce electromigration in interface interface?
Interface electromigration is dominant for p < 0.7, but they saw an order of magnitude increase in average drift velocity for 0.9 > p > 0.7. While in theory, larger grains could reduce electromigration, controlling grain size in nanometer-scale features is extremely difficult.
Is there an electromigration pathway for thin barrier layer materials on copper?
However, as new, thinner barrier layer materials are introduced to increase the copper cross-section, they can bring adhesion and electromigration concerns with them. So far, typically the most important electromigration pathway has been along the top surface, as adhesion between the dielectric barrier and the copper is typically weak.