Turn Up The Heat

The biggest worry in 3D stacking may not be as big a worry as everyone feared.


For the better part of two years talk of 3D stacking has been filled with concerns about thermal issues. If you stack logic on logic or memory on memory or CPU on CPU, the chance of causing a fatal failure in the circuitry was assumed to be very high.

It turns out that may not be the case after all. Companies working with early prototypes of 3D stacks say silicon itself may be one of the best conductors of heat and removing the heat from the chip. It sounds odd, but early tests show this is working.

Clearly, nothing is ever as simple as it sounds in advanced semiconductor designs. There are still huge problems to work out in 3D with signal integrity, electrostatic discharge, TSV interconnects and automated tools and models. No one is sure how IP will react in this type of environment, and considering the amount of IP being used in a chip continues to grow understanding how it behaves in context is critical.

Nonetheless, there is at least one positive piece of information to emerge from all this about the biggest worry. And there’s nothing wrong with some good news every now and then.

–Ed Sperling