Integrated femtosecond-laser workflow for decapsulation, delayering, and cross-sectioning of advanced package-on-package devices

Advanced packaging devices integrate multiple heterogeneous materials and components (e.g., mold compounds, redistribution/interposer structures, stacked memory, and logic dies) into compact assemblies whose failures can propagate into high-impact system-level outages. High-resolution, layer-by-layer 3D imaging is therefore essential for (i) failure analysis (FA) and root-cause determination, (ii) verification and validation (V&V) via as-designed versus as-built comparison, and (iii) security-focused inspection aimed at identifying unintended or malicious structural modifications. However, conventional approaches-mechanical polishing, chemical etching, and focused ion beam (FIB) delayering-are often slow, limited in precision, inconsistent over large areas, or difficult to scale for systematic workflows. In this work, we have shown that laser delayering can promise an effective alternative that is simultaneously fast and precise. Here, we demonstrate an integrated femtosecond-laser workflow for advanced package-on-package deprocessing that combines decapsulation, DRAM/component removal, sequential redistribution-layer exposure and removal, and targeted logic-die cross-sectioning on a single laser-processing platform. Process outcomes were validated using laser-scanning confocal microscopy for high-fidelity surface topography and scanning electron microscopy (SEM) for microstructural assessment. The results demonstrate a practical, rapid, and reproducible pathway for advanced-package system deconstruction and design reconstruction workflows supporting FA, V&V, and hardware assurance.