Delaminations

Pictured

Time Domain Imaging (TDI)™
Utilizes an echo (amplitude & polarity) arrival ‘time’ as a reference, such as standard A-Scan, B-Scan and C-Mode type images.

Delaminations

Solar Cell Concentrator Delaminations - Application Note 904

Delaminations

Sample & Method

In the image the echoes from the ultrasonic transducer were gated on the interface between the solar cell die attach and the substrate.

Result

The strongest signals were reflected from the localized regions shown in red. These regions are due to a delamination between the solar cell and substrate (die attach). These types of delaminations are important defects for solar cell concentrator systems where large amounts of heat need to be dissipated due to the focusing of the sun onto a very small area the size of the entire solar cell. Also, note the remnant of the solder material's original placement in the center of the cell, seen here as a slight material variation in the grey scale.