Voids in Solder

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.

Voids in Solder

Multi Chip Module (MCM) Direct Bond Copper Defects - Application Note 1066

Voids in Solder

Sample & Method

This rectifier has three ceramic substrates solder bonded to a copper base. The image was generated at 50 MHz by focusing through the copper base to the copper base/ceramic substrate interface.

Result

The black areas observed in the substrate regions (multi-colored areas) are large and small voids in the solder. Since heat dissipation is critical in rectifiers, the reduction in heat-sink efficiency by these voids is significant.