Destructive Inspection
High energy gallium ion beams provide the capability to remove precise volumes of material from a semiconductor package or printed circuit board assembly at a nanometer scale. This process known as focused ion beam microsectioning creates a clean cross-section of internal features for scanning electron microscopy analysis. Sub-micron accuracy allows the operator to isolate specific vias or solder joints that exhibit suspected voids or delamination.
Precise material removal happens without mechanical stress or shear forces that frequently damage brittle interconnects during conventional diamond saw cutting. The primary output provides a planar view into the internal layer registration and intermetallic compound thickness.
Instrumental Application
Milling occurs inside a vacuum chamber where the ion source accelerates charged particles toward the targeted surface of a component. Focused ion beam microsectioning follows a sequential removal pattern to reveal structural anomalies like pad cratering or micro-cracks in conductive traces. Gas injection systems assist the process by depositing protective platinum or tungsten layers over the area of interest to prevent curtaining effects during the excavation.
Automated stages permit the alignment of these site-specific cross-sections with CAD data models to confirm physical dimensions against design specifications. High resolution imaging of the exposed plane confirms the integrity of galvanic deposits and organic substrate materials.
Failure Analysis
Detection of intermittent electrical shorts often requires the exposure of dense multilayer regions where traditional physical sectioning destroys the evidence. Focused ion beam microsectioning exposes the transition between plating layers and dielectric materials to isolate current leakage paths in high density interconnects. Consistent application of this technique facilitates the identification of manufacturing defects including incomplete barrel filling or trapped impurities in the laminate.
Stable beam currents prevent excessive thermal loading of the sample during the operation. Precise geometric removal verifies that the physical structure of an assembly conforms to the microscopic requirements of high reliability applications.
