researchers at the fraunhofer institute for reliability and microintegration izm in berlin and dresden, germany, as part of the carricool project supported by ibm, have developed a novel cooling method for high-powered processors that incorporates microchannels into the silicon interposer to cool the chips from the top and bottom with liquid cooling.

the integration of microchannels into the silicon interposer allows for the first time to cool a processor also from the bottom and thereby increase the computing power. (fraunhofer izm)

according to a report from fraunhofer, “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.”

interposers act as a layer between the pcb and the chip to provide the electrical supply to the processor. the fraunhofer researchers inserted microfluid channels to circulate coolant.

“the particular challenge was not only to integrate the small channels into the interposer, but also to hermetically seal them and thus to separate them from the electrical paths,” the article continued.

in order to accomplish this, researchers made interposers of two silicon plates and designed horizontal cooling channels with vertical electrical channels. to avoid contact between the coolant and the electrical vias, each of the contacts is individually sealed.

this brings the cooling system much closer to the processor than previous attempts and enables cooling on both sides of the chip rather than the standard method of placing a heat sink on top or using fans to cool it.

“as if the cooling system were not enough,” the report continued, “the fraunhofer researchers additionally integrated voltage regulators for the power supply as well as optoelectronic components for data transmission into the interposer. while the voltage regulator supplies the processor with the appropriate operating voltage, the optoelectronics converts electrical signals from the processor into light signals.”

this enabled large amounts of data to be transmitted with high signal quality compared to copper lines that lose data at increased rates. the researchers hope this will be a step forward in high-performance computing.