Microwave evaluation of electromigration susceptibility in advanced interconnects

Area of Science:

• Electrical Engineering
• Materials Science
• Semiconductor Manufacturing

Background:

• Traditional metrology methods are insufficient for nano-scale integrated circuits (ICs).
• Reliability challenges in fabricating three-dimensional integrated circuits (3D-ICs) using through-substrate-vias (TSVs) hinder mass production.
• Novel metrology approaches are essential for understanding and controlling IC reliability.

Purpose of the Study:

• To investigate reliability issues preceding physical damage in copper-filled TSVs using microwave propagation characteristics.
• To establish a correlation between microwave signal parameters and the physical state of TSVs under stress.
• To provide a non-destructive method for assessing TSV reliability during fabrication.

Main Methods:

• Utilizing microwave insertion loss and group delay measurements to probe TSV integrity.
• Subjecting copper-filled TSVs to varying temperatures and direct current magnitudes to simulate operational stress.
• Analyzing the relationship between microwave signal perturbations and electromigration-induced defects.

Main Results:

• Microwave insertion losses increase with rising test temperatures, indicating defect mobility at the Cu-TiN interface.
• Group delay increases with higher direct current magnitudes, attributed to resistive heating effects.
• Microwave parameters serve as sensitive indicators of pre-failure conditions in TSVs.

Conclusions:

• Microwave propagation characteristics offer a viable non-destructive metrology for nano-scale IC reliability.
• Understanding defect dynamics and thermal effects via microwave analysis is crucial for 3D-IC fabrication.
• This technique facilitates early detection of potential failures in TSVs, improving manufacturing yields.