Meaning
Destructive failure analysis technique where a sample is encapsulated in resin and sliced through a coordinate of interest to reveal internal composition. The resulting surface is polished using increasingly fine abrasives until the physical features are visible under a light microscope or scanning electron device. It allows engineers to inspect the thickness of metal platings and the integrity of solder interfaces and the presence of internal voids.
Preparation Flow
Technicians start by securing the target in a mounting cup and pouring a fast curing epoxy over the edges. After the plastic hardens the block goes through a grinding machine to expose the precise vertical plane where the measurement is needed. Cooling liquids prevent heat from melting delicate components during the high speed cutting.
A final chemical etch highlights the boundaries of individual grains.
Interface Analysis
High quality microstructural cross-sectioning shows how layers of different materials have merged at the molecular level. Inspectors look for intermetallic compound layers that are either too thick or too thin to maintain a durable connection. Voids inside a copper fill are identified as dark spots that suggest an underlying process error in the plating tank.
Measurements of these dimensions determine the pass or fail status of the whole batch.
Verification Limit
This method yields a single view of reality at one specific coordinate which may not represent the rest of the object. Multiple samples are typically taken to ensure the findings carry statistical weight for the production run. Findings are saved in digital reports with high resolution imagery for client review.
This analysis remains the ultimate evidence in reliability disputes between the lab and the assembly house.
