cross-sectioning (package)

**Cross-Sectioning** is a **destructive failure analysis technique where a packaged IC is ground, polished, and examined under a microscope** — revealing the internal structure of the package, solder joints, wire bonds, die attach, and silicon layers in cross-sectional view. **What Is Cross-Sectioning?** - **Process**: 1. **Encapsulation**: Mount sample in epoxy resin. 2. **Grinding**: Remove material to approach the target plane (SiC paper). 3. **Polishing**: Fine polishing to mirror finish (diamond paste, colloidal silica). 4. **Imaging**: SEM or optical microscope at the cross-section face. - **Target**: Specific solder balls, wire bonds, vias, or die features. **Why It Matters** - **Root Cause Analysis**: Direct visualization of cracks, voids, delaminations, and contamination. - **Process Validation**: Verifying solder joint shape (hourglass), intermetallic thickness, and layer integrity. - **Gold Standard**: The most definitive FA technique — "seeing is believing." **Cross-Sectioning** is **the autopsy of electronic packages** — cutting open the device to directly observe its internal anatomy.