Practical Interpretation of Die Crack Origin in Semiconductor Packages Using Multi-Mode Scanning Acoustic Microscopy with B-Scan and TAMI Analysis
Practical Interpretation of Die Crack Origin in Semiconductor Packages Using Multi-Mode Scanning Acoustic Microscopy with B-Scan and TAMI Analysis
Wednesday, October 7, 2026: 5:40 PM
Summary:
This work demonstrated that multi-mode Scanning Acoustic Microscopy (SAM) combining C-scan, B-scan, and TAMI analysis is an effective methodology for die crack origin interpretation and crack propagation characterization in semiconductor packages. Conventional C-scan inspection was found to be effective for crack detection; however, it provided limited information regarding crack initiation location, crack propagation depth, and internal fracture behavior. By integrating B-scan cross-sectional imaging with TAMI multi-gate Time-of-Flight (TOF) analysis, the crack propagation path, propagation direction, and internal damage profile could be interpreted with significantly improved confidence. Different mechanical denting conditions produced distinctive acoustic signatures and fracture morphologies. Top-side denting generated localized and asymmetric crack propagation concentrated near the die surface, while bottom-side denting resulted in broader vertical fracture propagation with severe internal silicon damage extending toward the die backside. The results further demonstrated that package structure strongly influences crack propagation behavior, with substrate-based BGA packages exhibiting improved mechanical stress distribution compared with leadframe-based packages. The TOF-based depth correlation methodology enabled more accurate estimation of crack propagation depth across multilayer package structures by correlating calibrated acoustic velocity values with internal interface responses obtained from TAMI scan analysis. The study also demonstrated the importance of correcting silicon depth interpretation due to the acoustic velocity differences between silicon and surrounding package materials. Physical verification through chemical decapsulation and backside deprocessing showed strong agreement with the acoustic imaging results, confirming the reliability of the proposed multi-mode SAM methodology. In addition, WLCSP analysis demonstrated that high-frequency transducers combined with B-scan analysis are capable of differentiating crack propagation occurring at the active circuit layer from backside silicon damage. Overall, this work establishes a practical interpretation guideline for die crack investigation using multi-mode SAM analysis and demonstrates its capability to improve failure origin interpretation while reducing the risk of misdiagnosis in semiconductor failure analysis. The methodology also provides a technical foundation for future development of acoustic defect image databases and AI-assisted failure analysis applications.
This work demonstrated that multi-mode Scanning Acoustic Microscopy (SAM) combining C-scan, B-scan, and TAMI analysis is an effective methodology for die crack origin interpretation and crack propagation characterization in semiconductor packages. Conventional C-scan inspection was found to be effective for crack detection; however, it provided limited information regarding crack initiation location, crack propagation depth, and internal fracture behavior. By integrating B-scan cross-sectional imaging with TAMI multi-gate Time-of-Flight (TOF) analysis, the crack propagation path, propagation direction, and internal damage profile could be interpreted with significantly improved confidence. Different mechanical denting conditions produced distinctive acoustic signatures and fracture morphologies. Top-side denting generated localized and asymmetric crack propagation concentrated near the die surface, while bottom-side denting resulted in broader vertical fracture propagation with severe internal silicon damage extending toward the die backside. The results further demonstrated that package structure strongly influences crack propagation behavior, with substrate-based BGA packages exhibiting improved mechanical stress distribution compared with leadframe-based packages. The TOF-based depth correlation methodology enabled more accurate estimation of crack propagation depth across multilayer package structures by correlating calibrated acoustic velocity values with internal interface responses obtained from TAMI scan analysis. The study also demonstrated the importance of correcting silicon depth interpretation due to the acoustic velocity differences between silicon and surrounding package materials. Physical verification through chemical decapsulation and backside deprocessing showed strong agreement with the acoustic imaging results, confirming the reliability of the proposed multi-mode SAM methodology. In addition, WLCSP analysis demonstrated that high-frequency transducers combined with B-scan analysis are capable of differentiating crack propagation occurring at the active circuit layer from backside silicon damage. Overall, this work establishes a practical interpretation guideline for die crack investigation using multi-mode SAM analysis and demonstrates its capability to improve failure origin interpretation while reducing the risk of misdiagnosis in semiconductor failure analysis. The methodology also provides a technical foundation for future development of acoustic defect image databases and AI-assisted failure analysis applications.