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scanning acoustic microscopy(sam)

brief introduction:

ultrasonic microscope (sat) is short for scanning acoustic tomography, also called sam (scanning acoustic microscope). the detection is using ultrasonic reflection rate with different density of material and energy of different features for analysis. using pure water as the medium transmission ultrasonic signal, the signal would be part of the reflection and transmission interface when meeting different material and the emission intensity varies because of the density of material. scanning acoustic microscope is to use this feature to test the material internal defects and change of imagine in accordance with the received signal.

purposes:

nondestructive testing of electronic components, led, the layer of metal substrate cracks and other defects (cracks, layer, voids, etc.); by the contrast of the image to identify material internal acoustic impedance difference and determine the shape ,size and of the defect.

applications: 

plastic package ic, chip, pcb, led

test flow：

to confirm the sample types→select the frequency probe→placed in - measuring device→to select the scan mode→scanning image→defect analysis

reference standard: 

ipc/jedec j-std-035 ,ipc/jedec j-std-020, mil-std 883g, gjb 548b

typical test images:

crack/die

delamination/die paddle	delamination /lead frame