Researchers from North
Carolina State University are developing a 3D central
processing unit (CPU) with the goal of boosting energy efficiency by 15 to 25%.
The work is being done under a $1.5 million grant from the Intel Corporation.
The computer industry has a great deal of interest in 3D integrated
circuits, which are vertically integrated chips that are connected by vertical
electronic connections—called through silicon vias—that pass through silicon
wafers. These 3D circuits would represent an advance over conventional computer
chips, which operate in only two dimensions.
“Under this grant, we are building a 3D CPU chip stack and will be solving
some of the problems currently facing the development of 3D CPUs,” says Paul
Franzon, PhD, a professor of electrical and computer engineering at NC State
and lead researcher on the project.
One problem the researchers plan to address is how to reconcile chips that
are designed and manufactured in different places to different specifications
so that they can work together in three dimensions. They will also address
questions concerning heat dissipation, since the 3D nature of the design would
otherwise lead to much higher temperatures within the machine.
“Our goal is to achieve at least a 15% improvement in performance per unit
of power, through architectural and circuit advances,” Franzon says.
The researchers plan to have a complete prototype developed in 2014, and
will also be addressing “test and yield” challenges—such as how manufacturers
can test individual CPU components to ensure they are functional. These
challenges are key to facilitating the manufacture of 3D CPUs.
In addition to Franzon, the research team includes Eric Rotenberg and Rhett
Davis, a professor and associate professor, respectively, of electrical and
computer engineering at NC State; and Krishnendu Chakrabarty, PhD, of Duke