Scanning Acoustic Microscopy Echo Phase Inversion for Package Failure Analysis
Acoustic phase inversion identifies package delamination by tracking 180-degree echo phase shifts caused by air gap impedance drop at internal material boundaries.
Package Failure Analysis
Diagnostic Procedure
Investigation protocols are deployed to determine the root cause of electrical or physical anomalies in semiconductor packages. This series of steps, package failure analysis, aims to locate the specific point of failure within the molded plastic or leadframe. It begins with non-destructive methods to avoid altering the internal structures.
The resulting findings guide corrective actions in both assembly processes and material selection.
Testing Workflow
The process begins with electrical characterization on a curve tracer to confirm the reported symptoms and pinpoint the faulty pins. After identifying the pin, package failure analysis employs acoustic microscopy or x-ray imaging to detect internal cracks, voids, or delaminated layers. If the non-destructive scan is inconclusive, technicians use lock-in thermography to locate heat-generating short circuits inside the molded package.
Physical Inspection
Once the region of interest is identified, destructive techniques are applied to expose the defect. This phase involves decapsulating the plastic molding compound with chemical solvents or using cross-sectional polishing to reveal internal wire bonds. Microscopic examination under a scanning electron microscope then allows for high-resolution evaluation of sub-micron features, which cannot be seen with optical microscopes.
These detailed findings help determine whether the failure was caused by a manufacturing defect or by electrical overstress during operation, giving engineers the necessary data to modify board designs or manufacturing tolerances.