As the demand for smaller microchips increases, issues with being able to meet the demand center largely around the ability to dissipate the heat they generate. But the addition of self-cooling elements to the chips is an solution that is being tested.

“This intrinsic limitation stands in the way of Moore's Law, which anticipates that microchips and transistors will continue to get smaller and smaller as computing needs and power increase. Without being able to overcome their hot flashes, continuing to miniaturize microchips poses a problem to computing,” the Inverse website notes.

Swiss researches have been working on integrating the cooling system directly with the chip itself. As Inverse states: “This approach could yield orders of magnitude improvements in efficiency to previously proposed cooling models, and bring computing into a new age of innovation”.

Currently heat extraction capabilities are fundamentally limited by the thermal resistance between the hardware - a semiconductor - and the packaging. The Swiss researchers are working on a chip that can integrate the cooling elements directly onto the chip. This “microfluidic-electronic co-design”, as they term it, can allow for controlled heat dissipation and management.

Current cooling methods rely on large amounts of water. Eac kilowatt hour of energy needs 2 gallons of water to cool it. Given US data centers are predicted to consume 73 billion kilowatt hours - they alone would need 220,000 Olympic size pools of water, Inverse explains.

Previous attempts to develop self-cooling chips have been done with the cooling elements built separately from the electronic elements and combined after their fabrication. These methods had issues with cost and thermo-related stress.

“Power electronics are solid-state electronic devices that convert electrical power into different forms, and are used in a vast array of daily applications — from computers to battery chargers, air conditioners to hybrid electric vehicles, and even satellites. The rising demand for increasingly efficient and smaller power electronics means that the amount of power converted per unit volume of these devices has increased dramatically. This, in turn, has increased the heat flux of the devices — the amount of heat produced per unit area,” Nature Magazine reports. 

"[This team] have made a breakthrough by developing... a system in which [cooling channels] are integrated and co-fabricated with a chip in a single die," writes report's author and mechanical engineer, Tiwei Wei. "The buried channels are therefore embedded right below the active areas of the chip, so that the coolant passes directly beneath the heat sources."

The team started with making the embedded cooling system and adding widened coolant channels onto the microchip’s substrate. The channels were sealed off with copper and the other electronic components were built directly on top of the chip.

Using a water coolant, the team designed an electronic component that converted alternating current (AC) electricity into direct current (DC) and tested it against a similar component without embedded cooling. Significantly higher efficiencies were seen and the researchers theorized that this system has cooling power up to 50 times greater than other conventional models.

And, because the fabrication approach uses existing systems, the researchers say it's already economically viable.

Caveats from Wei include the materials used for the testing need long-term testing in multiple environments, water as a coolant may not be the right long-term solution

SOME CAVEATS — But, this design isn't exactly a home run, says Wei. Wei points out in his report a few structural concerns with the design; namely the material used for the substrate surface and an adhesive used to connect the coolant channels during fabrication. For both, the long-term stability and effectiveness in different environments, for example, in temperatures associated with typical microchip manufacturing processes, are cause for concern.

Likewise, water as a coolant for this system may not be a long-term solution, either — given how electronics and water typically don't get along. "Despite the challenges still to be addressed, [this] work is a big step towards low-cost, ultra-compact and energy-efficient cooling systems for power electronics," Wei added.

Smaller than a coin, this self-cooling microchip backs some hidden secrets.Van Erp et al. / Nature