Issue link: https://iconnect007.uberflip.com/i/1533904
40 SMT007 MAGAZINE I APRIL 2025 ufacturing, the disproportionate dimensions made it impossible to get enough detail while spinning the board around. Fortunately, laminography scans were invented that allowed for a different angle of rotation that was more conducive to parts of this shape. Employing this trajectory for advanced packaging inspection has many advantages over CT. While CT of even small packages would still require movement away from the X-ray source, decreasing magnification and, there- fore, detail, or allowing the highest level of detail to be gathered only in the corners or other limited regions, laminography scans can be achieved anywhere of interest. is strategy, along with precision move- ment throughout a large enough sys- tem, allows for a tray of components to be inspected in one batch run, increasing pro- ductivity many times over. Scan time variations yield varying results One of the other variables that affects resulting image quality is scan time. Many tests have been done with acceptable results that were achieved in under 10 minutes. However, longer scan times were also tested, which showed improved quality, eventually producing diminishing returns aer an hour or so. Necessary image quality and therefore scan time, will need to be determined on a case by case basis. Defect detectability Putting all this technology together yields a system that can detect a wide variety of defects including the following: • Tilting between layers • Missing interconnects • Bridging of interconnects • Bulging interconnects • Undersized bumps • Shied layers • Voiding within interconnects Figure 5: Results of scan times between eight and 33 minutes. Figure 6: Head-in-pillow defect visible on 65 µm bump.