Book contents
- Electromigration in Metals
- Electromigration in Metals
- Copyright page
- Dedication
- Contents
- Preface
- 1 Introduction to Electromigration
- 2 Fundamentals of Electromigration
- 3 Thermal Stress Characteristics and Stress-Induced Void Formation in Aluminum and Copper Interconnects
- 4 Stress Evolution and Damage Formation in Confined Metal Lines under Electric Stressing
- 5 Electromigration in Cu Interconnect Structures
- 6 Scaling Effects on Microstructure of Cu and Co Nanointerconnects
- 7 Analysis of Electromigration-Induced Stress Evolution and Voiding in Cu Damascene Lines with Microstructure
- 8 Massive-Scale Statistical Studies for Electromigration
- 9 Assessment of Electromigration Damage in Large On-Chip Power Grids
- Index
- References
9 - Assessment of Electromigration Damage in Large On-Chip Power Grids
Published online by Cambridge University Press: 05 May 2022
- Electromigration in Metals
- Electromigration in Metals
- Copyright page
- Dedication
- Contents
- Preface
- 1 Introduction to Electromigration
- 2 Fundamentals of Electromigration
- 3 Thermal Stress Characteristics and Stress-Induced Void Formation in Aluminum and Copper Interconnects
- 4 Stress Evolution and Damage Formation in Confined Metal Lines under Electric Stressing
- 5 Electromigration in Cu Interconnect Structures
- 6 Scaling Effects on Microstructure of Cu and Co Nanointerconnects
- 7 Analysis of Electromigration-Induced Stress Evolution and Voiding in Cu Damascene Lines with Microstructure
- 8 Massive-Scale Statistical Studies for Electromigration
- 9 Assessment of Electromigration Damage in Large On-Chip Power Grids
- Index
- References
Summary
A very different picture of the redistribution of metal density and stress, caused by electric stressing, can be expected in multibranch interconnect structures formed by connected metal lines within the same metal layer. The absence of diffusion barriers in line junctions allows atoms to freely migrate between lines along the trajectories of the current carriers. When a multibranch structure includes metal lines that are connected in parallel, the creation of a void in one of the parallel branches does not necessarily result in a failure, which contrasts with what happens in a single line segment, because current can continue to flow in the unvoided parallel lines. The on-chip power/ground (p/g) grid is an example of such electrically redundant multibranch structures. In this chapter, we review a recently developed assessment methodology of the p/g grid MTTF and describe a novel experimental technique that could validate the proposed methodology. EM assessment performed on the grids with tens of millions of nodes has shown that the formation of the first void alone didn’t cause a grid failure. A failure criterion of 10% voltage drop increase was met due to cumulative effect of nucleation of several voids and their growth in the failed branches.
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- Electromigration in MetalsFundamentals to Nano-Interconnects, pp. 380 - 413Publisher: Cambridge University PressPrint publication year: 2022