Work

Post-Bonding Crack-Induced Di-Cantilever Bending (PBC-DCB): A Novel Method for Quantitative Evaluation of Bonding Strength for Wafer-to-Wafer and Die-to-Wafer Hybrid Bonding

Year: 2025

Type: article

Abstract: To address the challenge of characterizing bonding strength in hybrid bonding, this paper proposes a method based on post-bonding crack-induced di-cantilever bending (PBC-DCB). The commonly used industrial blade insertion (BI) method only measures the edge strength of wafer-to-wafer samples via bevel geometry, failing to characterize the wafer center or die-to-wafer samples (as they lack a bevel) and exhibiting limited accuracy due to irregular crack edges. This study develops a di-cantilever beam test initiated by a specially prepared post-bonding notch. By deriving the relationship between load–displacement and bonding strength based on fracture mechanics and optimizing sample preparation and testing parameters, quantitative measurement of interface fracture strength is achieved. Experimental results show the method has a deviation < 5% from BI with better repeatability, verifying its reliability. It successfully distinguishes bonding strength between wafer center and edge and reveals that SiCN dielectric layers have 17.34% higher strength and better uniformity than SiO2. This provides a reliable testing tool for hybrid bonding quality and process optimization, with broad prospects in industrial production and scientific research.

Source: Micromachines

DOI: 10.3390/mi16121304