Acoustic Microscopy Imaging

The Acoustic Microscopy method uses a high frequency ultrasound transducer to emit sound waves that are either echoed by or transmitted through a material. The resulting acoustic signature or waveform may be interpreted to determine variations of acoustic impedance within a sample. Differences in acoustic impedance may indicate a change in material densities or separation at an interface. Images can also be generated through a pulse-echo, a means by which the user mechanically scans the transducer across a sample in a raster pattern as it emits and receives an ultrasound signal. An immersion fluid medium is typically used to acoustically couple the samples while analysis is performed.

Acoustic microscopy is a non-destructive screening technique that offers unique insight into the caliber of package and device construction. The advantages of this screening method include the ability to detect void formations, delaminations, cracks and fractures, as well as various other internal defects that may be hidden within inherently susceptible materials and device types. These device types include, but are not limited to:

  • SOIC
  • BGA
  • CSP
  • Encapsulating Materials
  • PCB
  • Molding Compounds
  • Flex Circuits

 

Additionally, the C-SAM device is instrumental in counterfeit detection. It can be used to scan for a wide range of component anomalies including original part markings on a remarked component, sanding marks not visible through other testing methods, and internal issues common in counterfeit components.

All analysis utilizing this method is conducted to IPC/JEDEC J-STD-035 and Acoustic Microscopy for Nonhermetic Encapsulated Electronic Components standards, as well as any additional client requirements.

Compliances

IPC/JEDEC J-STD-035

Information Obtained

  • Voiding within device
  • Delamination
  • Ghost part markings
  • Resurface material

Instrumentation
Sonoscan D-9000 C-Mode Scanning Acoustic Microscope (C-SAM)

Available to the analysis procedure is the usage of a Through-Scan. Through-Scan transmission mode generates images based on variations in acoustic impedance. This mode is often necessary to verify defects observed during C-Scan mode analysis.

Common Applications

Ceramic Capacitor Defects
Ball Grid Arrays (BGA)
Metal Ball Grid Arrays (MBGA)
Plastic Package Defects
Plastic Encapsulated IC's
Hybrids
Die Attach Defects
Flip Chips
Chip Scale Packages (CSP)
Bonded Wafers
 
 
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