Scanning acoustic microscopy spots reflow damage

A National Physical Laboratory product story

Edited by the Electronicstalk editorial team Apr 6, 2005

The NPL has developed broad expertise in applying scanning acoustic microscopy for assessing the level of delamination in printed circuit boards and die cracking inside electronic packages.

The National Physical Laboratory has developed a broad expertise in applying scanning acoustic microscopy (SAM) - a nondestructive tool for assessing the level of delamination in printed circuit boards and die cracking inside electronic packages.

Typical applications include: the assessment of plastic compounds developed for lead-free components that must withstand the more demanding reflow process requirements; identifying damage in integrated circuits and MEMS structures; analysing the level of leadframe delamination after various assembly steps and testing; and delamination of underfill materials for flip-chips.

The main advantage of using SAM in electronics is that total reflection occurs where any gap appears: void, delamination, fracture or crack.

This means defects are readily apparent and can be measured.

The acoustic wave velocity is dependent on the acoustic impedance, and materials like silicon have high values in contrast to polymers and hence good contrast is available when investigating structural properties.

NPL can offer a comprehensive SAM testing service on a wide range assemblies and components.