Failure Analysis for Electronic Packaging Materials: A Comparative Study of Pulsed Thermography and Lock-in Thermography

Electronic packaging plays a critical role in ensuring the reliability and performance of electronic systems. As various materials are used in these systems, each with distinct properties, failure analysis of each is key to improving overall system reliability. This paper presents a comparative study of two non-destructive testing (NDT) methods—pulsed thermography (PT) and lock-in thermography (LIT) — for failure analysis in electronic packaging materials. The study focuses on defect detection in copper (Cu), aluminum (AI), and polymer, which are widely used in electronic packaging due to their distinct thermal characteristics. Experimental results are evaluated using signal-to-background contrast (SBC). To enhance thermal contrast, three post-processing techniques—pulse phase thermography (PPT), principal component thermography (PCT), and thermographic signal reconstruction (TSR)—were applied to the PT results. These results were then compared with the optimal performance of LIT. The findings demonstrate that both methods have distinct advantages and limitations: PT offers faster detection, while LIT provides higher sensitivity for materials with higher thermal diffusivity. This study enhances the understanding of how these techniques can be effectively applied in electronic packaging failure analysis.