Virtual Rescanning Mode (VRM)™

Pictured

Flip Chip
300 MHz image showing void (red) in underfill.

Virtual Rescanning Mode (VRM)™

With one scan, Sonoscan’s Virtual Rescanning Mode collects comprehensive acoustic data at every X, Y, and Z coordinate. This detailed matrix of acoustic data is then digitally stored, allowing the operator to “virtually rescan” the component at any time, using the most common imaging modes and new techniques.

Components that are placed into high reliability situations (e.g., satellites, airplanes, missile systems) are often analyzed using this feature to provide a more complete archival documentation of the component for future evaluation.

The main capabilities of VRM include Time Domain Imaging (TDI), Frequency Domain Imaging (FDI), B-scan (cross-sectional) Imaging, ZipSlice/3V Imaging and Profile (depth of feature) Imaging. Each imaging mode provides unique information that combines to yield a more comprehensive analysis of a sample.

The following example illustrates the value of Sonoscan’s Virtual Rescanning Mode:

A flip chip was scanned using VRM prior to undergoing destructive physical analysis. Although the sample no longer existed, it was 'virtually rescanned' at 300 MHz to evaluate underfill and bump quality. Later, the part was 'virtually rescanned' in the frequency domain at 195 MGz to reveal solder ball variations.
From the control screen the operator has access to each of these imaging modes. Once the acoustic data has been stored using VRM, the data can be analyzed by using specialized software on any compatible computer. With this software, each of the imaging modes is generated from the original VRM data and since the data is stored digitally the component may be virtually inspected as many times as desired. This allows for a more complete analysis of the part, archive storage and unlimited refinements of the inspection at a later date.