Scanning Acoustic Microscopy, SAM
SAM is an advanced inspection technique that uses ultrasound to observe the
internal structures of materials at high resolution.
It enables non-destructive analysis of microscopic structures and internal defects that are
invisible to the human eye, playing a critical
role across both research and industrial applications.
SAM is widely used in the semiconductor and electronics industries, where it
detects defects such as voids, cracks, and delamination
inside microelectronic packages. By identifying these internal failures, SAM ensures product
reliability and has become an essential
inspection tool for failure analysis and quality control processes.
Principle
SAM is a non-destructive inspection technology that visualizes the internal
structure of a
specimen by leveraging the
high penetration
capability and frequency characteristics of
ultrasound.
When ultrasonic waves generated by a transducer propagate through a specimen, scattering,
absorption, and reflection occur depending
on the material’s density and elastic
properties.
These phenomena arise from differences in acoustic
impedance between internal
layers
(Acoustic Impedance, Z = ρ·c), and by analyzing the resulting reflected
echoes—specifically their time-of-flight (ToF), phase shift, and
amplitude—internal defects
and
material non-uniformities can be evaluated with high precision.
The ultrasonic transducer converts the received echoes into electrical signals, which are then
digitized through an analog-to-digital converter
(ADC, digitizer) and
processed using
advanced
signal processing algorithms.
The processed data are reconstructed into two-dimensional(2D) and three-dimensional(3D) acoustic
images,
enabling high-resolution visualization
of structural anomalies such as voids,
delamination, and
cracks within the specimen.