Collaborators from IBM and Berlin's Fraunhofer Institute have demonstrated a method of using water to cool processors arranged in 3-D stacks.

Stacking chips in three dimensions is an approach to creating better number crunching hardware, but IBM said that the 3-D chip stacks had an aggregated heat dissipation 10 times greater than an average hotplate.

Bruno Michel, manager of the chip cooling research efforts at the IBM Zurich Lab, said, "With classic backside cooling, the stacking of two or more high-power density logic layers would be impossible.”

To address the cooling problem, the collaborators have piped water into cooling structures, "As thin as a human hair between the individual chip layers in order to remove heat efficiently at the source," they said. The cooling structures, "had to be fabricated to an accuracy of 10 microns, 10 times more accurate than for interconnects and metallisation in current chips," it added.

The advance is part of a research effort, said IBM to allow, "the reuse of heat generated by data centres by capturing water at its hottest and piping it into the building’s water and heating systems."