Reliability Investigation of W2W Hybrid Bonding Interface: Breakdown Voltage and Leakage Mechanism

The electrical reliability of 1 µm pitch wafer-to-wafer (W2W) Cu/SiCN hybrid bonding interface is evaluated. Breakdown voltage distributions of the W2W hybrid stack were acquired using the controlled-IV method. Assuming a power law model, extrapolation towards use conditions confirm a lifetime above 10 years, with a power law exponent above 10 for temperatures under 175 °C. The conduction mechanism along the Cu/SiCN hybrid bonding interface is found to be Poole-Frenkel emission with energy barrier equals 0.95 eV. Mobile copper could only be observed at temperatures above 200 °C and for fields above 1.5 MV/cm, confirming the good robustness against copper drift for this bonding interface.