Package-on-Package (PoP)
Complete Package on Package (PoP) Solutions with Both Top and Bottom Package Technologies
STATS ChipPAC’s Package-on-Package (PoP) family includes a stackable FBGA as the bottom PoP package (PoPb). PoPb is typically an ASIC or baseband device with land pads placed on the top periphery of the package surface to enable the stacking of a second FBGA or PoP top (PoPt) above. PoPt consists of memory or other silicon functionally assembled, tested and yielded independently. The two packages are combined by reflowing together (usually performed simultaneously) on the application board, to form PoP (Z-interconnection with solder ball). STATS ChipPAC offers the flexibility of stacking up to two devices in the PoPb and up to five devices in the PoPt.
Advantages
As multi-die stacking becomes increasingly more common, known good die issues are critical for cost saving and throughput yield. For example, in a four die stack package, a single die can render the entire package unusable even if the other three die are fully functional. One way to overcome this problem is by using package stacking which can overcome known good die issues since die functionality can be checked after being packaged and before being placed on top of another known good package.
PoP can provide an overall low profile as stacked and allows individual packages to be tested prior to stacking. This PoP approach is attractive to device manufacturers and end customers. Device manufacturers can focus on their core competencies and not worry about integrating other devices (test and yield implications) into the packages they sell. The end customer can leverage traditional sources for each device type and has more flexibility to configure devices as needed for a particular product and market.