Time Domain Imaging (TDI)™
After the VRM data has been collected, time domain images can be created from the archived data. The images shown were created in this manner on a QFP (Quad Flat Pack), a plastic encapsulated microcircuit (PEM). To generate time domain images the VRM file is opened to the A-scan data. Since the A-scan data is digitally saved for every pixel location across the component, an electronic gate can be adjusted to select the depths (time domain) to inspect within the part. Individual gates were selected within the A-scan to produce images of the top surface of the package, the top side bulk mold compound and the top side leadframe and die interfaces together, as well as separate images of the die surface and die attach.