The questions we hear from mid-end production folks concerned with package-related device reliability at the wafer level often sound like this —
• We’ve had some interconnect issues on diced die. Can we look at them at the wafer level before dicing?
• Can we find out how consistent our MEMS cavity seals are?
Sonoscan’s twin-transducer high-throughput AW300™ automated wafer scanner scans two 300mm wafers at a time. Or two 200mm wafers. Or two 150mm wafers.
Its wafer-handling robot can accept various types of wafer carriers and precisely positions each for scanning.
The two ultrasonic transducers each scan a wafer at high speed and high ultrasonic frequency (= high resolution). Gap-type defects (meaning non-bonds, delaminations, voids and cracks) are reported by their exact location, which permits their later removal after dicing.
Gap-type defects can occur in 3D IC, chip on wafer, chip stack on wafer, direct bonded wafers, anodic bonded wafers, and intermediate bonded wafers.
Even very tiny defects cannot escape detection. Of all possible internal features, gap-type defects reflect ultrasound most strongly, and therefore send back the strongest return echo signals.
Have a question of your own? Send it to Sonoscan’s expert, Ben Liu at [email protected]