Stefan Mileschin

At Flash Memory Summit this week, Toshiba is showing off a NAND flash device packaged using through-silicon vias rather than traditional wire-bonded connections.

The NAND flash currently on the market is typically produced in the form of a die with a capacity like 128Gb (16GB). The popular SSD form factors don't have enough surface area to fit dozens of those chips, and SSD controllers don't have the pin count to connect to that many independently, so several chips are stacked in a single postage-stamp sized package. The traditional way of connecting the individual dies in a stack is to use the same technique as for a single-die package: bonding a thin gold wire between the edge of the die and the package substrate or external pins. The downsides are that it requires a lot of wires and the edges of the dies in the stack need to be exposed somehow, either by staggering them or by putting a spacer between each layer.

http://www.anandtech.com/show/9520/t...-to-nand-flash