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Researchers unveil polymer-based TIM

Researchers unveil polymer-based TIM

A thermal interface material created from aligned nanofibres of polymer could be the future of chip cooling, offering impressive performance in a layer just three microns thick.

Researchers at the Georgia Institute of Technology have announced what they claim is a novel way of improving the transfer of heat from computer chips to heatsinks: a polymer-based thermal interface material (TIM) which can be applied in a layer just three microns thick.

Polymers may not be the obvious choice when it comes to conducting heat or electricity, but the team has developed a method which aligns the polymer chains themselves in nanofibres - avoiding problems with the previous technique of forming aligned crystalline structures which are too brittle to be of use. Using polythiophene, the team has been able to modify the polymer's structure in such a way to boost the thermal conductivity 20-fold and yet have the new material operate reliably at temperatures of up to 200 degrees Celsius.

'Thermal management schemes can get more complicated as devices get smaller,' explained Baratunde Cola, assistant professor of mechanical engineering at the Georgia Institute of Technology. 'A material like this, which could also offer higher reliability, could be attractive for addressing thermal management issues. This material could ultimately allow us to design electronic systems in different ways.'

The team's initial target market is high-temperature devices which can't use solder as the thermal interface material. Commonly used to connect large heatspreaders to the far smaller die on processors, solder proves problematical when the temperature of the device begins to approach that required to turn the solder molten once more. 'Polymers aren’t typically thought of for these applications because they normally degrade at such a low temperature,' Cola explained. 'But these conjugated polymers are already used in solar cells and electronic devices, and can also work as thermal materials. We are taking advantage of the fact that they have a higher thermal stability because the bonding is stronger than in typical polymers.'

Another advantage of the new material is that it can be applied in a layer just three microns thick while still maintaining its performance, compared with the usual 50 to 75 micron layer required of traditional thermal interface materials. The thinner the layer, the closer the heatsink can be positioned to the chip being cooled - and the more efficient the heat transfer. Stresses normally associated with thermal cycling - constant heating and cooling cycles, common to semiconductors as they are loaded and unloaded - are also avoided, Cola claims.

While Cola has already applied for a patent on the technique and formed a start-up company, Carbice Nanotechnologies, for its commercialisation, it could be a while before it's product-ready: Cola admits that the theoretical processes behind the manufacturing are not yet fully understood, and the technique itself requires further development to improve yields.

The team's work is published in the latest Nature journal, under the title 'High thermal conductivity of chain-oriented amorphous polythiophene.'

6 Comments

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Dave Lister 1st April 2014, 10:25 Quote
I do hope intel are paying attention to this.
Maki role 1st April 2014, 10:36 Quote
Quote:
Originally Posted by Dave Lister
I do hope intel are paying attention to this.

If it's cheap enough, I can't imagine they wouldn't be. In any case it sounds like it would make for a neat marketing line for their top end components anyway. I wonder what the real world differences of this technology would be for applications that are already okay with a solder interface or similar? It sounds like this could be very useful for certain applications where that's difficult, but not quite so significant elsewhere where that isn't a bottleneck.
Pookie 1st April 2014, 10:50 Quote
I would prefer that the chips were more efficient and didn't produce so much heat in the first place.
maverik-sg1 1st April 2014, 11:17 Quote
Quote:
Originally Posted by Pookie
I would prefer that the chips were more efficient and didn't produce so much heat in the first place.

You still need to be able to draw the heat away from the components, TIM is used to transfer any heat to the heat spreader which can then be carried away by heatsinks etc....
Quote:
Originally Posted by Dave Lister
I do hope intel are paying attention to this.

100% hope so too!!

The downfall of their last two CPU's has been the TIM, when it comes to overclocking the TIM has been proven to be very inefficient at heat transfer to the heatsink and because of that the achievable overclock is capped.

I am still running with my trusty SB 2500k which, when overclocked to 4.8ghz, offers similar (close enough) performance to the throttled OC of either an IB or Haswell CPU, the performance gap is so close, there's no reason for an overclocker to upgrade.

Having a better TIM would allow the cpu's to clock as well as previous generations and offer everyone a reason to upgrade - Intel have lost sales on two generations of CPU's because they saved $0.02 (or less) per cpu on TIM.
Guinevere 1st April 2014, 11:39 Quote
Quote:
Originally Posted by Pookie
I would prefer that the chips were more efficient and didn't produce so much heat in the first place.

But they are.

No matter how efficient and cool you make them people will want to bung lots of them together and make something crazy powerful. Titan Z has what... 5,760 CUDA cores?

If someone made chips 90% cooler over night you'd see passively cooled laptops (Like tablets are and the rumoured Macbook Air refresh will be) but you'll also see much more powerful high end rigs with a thermal demand not that different to what we have today.

The difference we have of late is plenty of options for cool passively cooled 'computers'... we just call them smart phones and tablets.
Corky42 1st April 2014, 12:21 Quote
Quote:
Originally Posted by maverik-sg1
Having a better TIM would allow the cpu's to clock as well as previous generations and offer everyone a reason to upgrade - Intel have lost sales on two generations of CPU's because they saved $0.02 (or less) per cpu on TIM.

It wasn't done to save money.
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