Microchannel cooling tech achieves higher processor performance
Mon 2 Oct 2017
New research is looking to further develop microchannel cooling technology in an effort to advance processor performance.
The CarriCool project, backed by IBM, sets out to better manage operating temperatures which can be a limiting factor for the computing power of processors.
Researchers at the Fraunhofer Institute have now discovered a new cooling method which integrates microchannels into the silicon interposer. The innovation allows for high-performance processors to be cooled from the underside, driving a significant increase in performance.
The team was also able to integrate passive components for voltage regulators, photonics ICs and optical waveguides into the interposer.
The study explains that when processors get too hot, they reduce their clock rate and operating voltage. In order to protect the CPU and motherboard from heat damage, the processors have to either reduce their computing speed or shut down entirely.
Until now, cooling elements have been used to avoid overheating, while fans are employed simultaneously to cool heat-sensitive components from above.
Now, the Fraunhofer team, led by Dr Wolfram Steller, Dr Hermann Oppermann and Dr Jessika Kleff, have found a way to cool microchips from the top, as well as below, using a liquid-based cooling system.
‘Microchannel structures with hermetically sealed vias are installed in the silicon interposer, which is located between the processor and the printed circuit board. The coolant is then pumped through the microchannels channeling off the heat from the processor,’ the paper explains.
The study notes that the interposers are responsible for the electrical supply and cooling of the processor. They act as a layer between the circuit board and the chip and are connected every 200 micrometres from top to bottom by electrical vias to guarantee the processor’s power supply and data transmission.
In order to effectively absorb heat and channel it away from the processors, the researchers further installed microfluid channels cross-linking the electrical vias, which allow the coolant to be circulated.
‘Up to now, the cooling structures are not very close to the computer core itself, which means the coolers are mostly applied from above,’ said Oppermann.
‘The closer you get to the heat source, the better the temperature can be limited or the output increased. In high-performance computing in particular, the data rates are continuously increasing. Therefore, it is important to have an effective cooling to ensure a higher clock rate. Previously used cooling systems were not so effective in this context. Now, with this new cooling system, the performance can be increased significantly,’ he added.
In addition to the cooling technology, the team also integrated voltage regulators for the power supply, as well as optoelectronic components for data transmission into the interposer.
The voltage regulators supply the processors with the appropriate operating voltage, while the optoelectronics convert electrical signals from the processor into light signals. This allows for even larger amounts of data to be transmitted with higher signal quality, compared to copper lines through which data loss increases with growing data rates.
Oppermann concluded: ‘By combining interposer, cooling, voltage regulators and optical interconnection technology, we have reached a new level of integration that allows smaller circuits with more power.
‘This is an important step in high-performance computing, as we achieve higher clock speeds in the same amount of space.’