Investigation on Electromigration-Induced Failure and Reservoir Effect in AlCu Interconnects.
Yuanxiang Zhang1, Guoquan Jiang1,2, Jingbo Zhao1,2
1College of Mechanical Engineering, Quzhou University, Quzhou 324000, China.
Micromachines
|April 26, 2025
Summary
Electromigration (EM) is a reliability issue in aluminum-copper (AlCu) interconnects. This study validates the atomic density integral (ADI) method for predicting EM failure, showing reservoirs improve interconnect lifetime up to a critical length.
Area of Science:
- Materials Science
- Electrical Engineering
- Reliability Engineering
Background:
- Aluminum-copper (AlCu) alloys are crucial interconnect materials in microelectronics.
- Increasing current densities in shrinking devices exacerbate electromigration (EM) concerns.
- Electromigration poses a significant reliability challenge for AlCu interconnects.
Purpose of the Study:
- To investigate electromigration-induced degradation in AlCu interconnects.
- To validate the atomic density integral (ADI) method for EM failure prediction.
- To analyze the impact of reservoir structures on interconnect reliability.
Main Methods:
- Fabrication of two-level AlCu interconnects with Ti/TiN barriers using 0.18 μm technology.
- Accelerated electromigration tests under varying current densities and temperatures.
- Numerical simulation using the atomic density integral (ADI) method on the ANSYS platform.
- Finite element modeling to study the reservoir effect.
Main Results:
- Void nucleation and evolution during EM degradation were observed.
- The ADI method accurately simulated experimental EM failure.
- Reservoir structures were shown to enhance the mean time to failure (MTTF) of AlCu interconnects.
- A critical reservoir extension length was identified beyond which no further lifetime improvement occurs.
Conclusions:
- The ADI method is a viable tool for predicting electromigration failure in AlCu interconnects.
- Reservoir engineering can effectively improve the reliability of microelectronic interconnects.
- Understanding the reservoir effect is crucial for designing robust electronic devices.
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