Scanning Acoustic Microscopy (SAM)

Scanning Acoustic Microscopy (SAM)

Scanning Acoustic Microscopy (SAM) is a non-destructive and non-invasive imaging technique which uses ultrasound signals to visualize the sample.

The working principle of SAM relies on the detection of how acoustic waves interact with material interfaces. The various modes of interactions include scattering, absorption, reflection, and transmission. Of these, SAM detect either reflected or transmitted acoustic waves to generate the final image. In a routine measurement, a sample is submerged in a coupling media (i.e. water) and subjected to high frequency acoustic waves generated by a piezoelectric transducer. The resulting echoes due to acoustic impedance (Z) contrast at the material interfaces are then analyzed to produce images.

Since sound waves can have high penetration depth, SAM is particularly powerful in imaging underlying and internal structures, as well as features that are difficult to resolve with optical techniques. It is often used to characterize microscopic feature (or defects) such as cavity, voids, cracks, and delamination.

What SAM is great for:

  • Voids, cracks, micro-cracks, delamination, cavity.
  • Biological tissues, medical implants, bones, teeth.
  • Quality control for semi-conductor industry such as wafers, SiC ingots, MEMS, die structures, microprocessors, LED, CMOS sensors, molded components, and packaging.
  • Underlying and internal structures

EXAMPLE OUTPUTS 

scanning acoustic microscopy
(Top) An optical image of a packaged device (Bottom) Internal delamination shown in red. Credit: PVA TePla

INSTRUMENTS USED FOR
Scanning Acoustic Microscopy (SAM)

PVA TePla 302 HD2 

 The 302-HD2 scanning acoustic microscope from PVA TePla incorporates an updated array of 2 transducers with synchronized autofocus for simultaneous image acquisition. This system can generate acoustic waves at frequencies up to 400 MHz, and is able to scan a vertical height range up to 320 mm.

PVA TePla 501 HD2

Like the 302-HD2 model, the 501-HD2 also incorporates an array of 2 transducers with synchronized autofocus and automated acoustic wave generation for simultaneous image capture. It is also able to produce waves at frequencies up to 400 MHz, but has the ability to scan over a greater vertical range: up to 500 mm.