One of the things that stops electronic devices from going faster is heat. That’s why enthusiasts go as far as using liquid nitrogen to cool CPU chips to maximize their overclocking potential. Researchers at Georgia Tech have been working on cutting fluid channels directly into the back of commercial silicon die (an Altera FPGA, to be exact). The tiny channels measure about 100 micron and are resealed with another layer of silicon. Water is pumped into the channels to cool the device efficiently.
A comparable air-cooled device would operate at about 60 degrees Celsius. With the water cooling channels cut into the die and 20 degree water pumped at 147 ml/minute, the researchers kept the chip operating about less than 24 degrees Celsius.
Even though water cooling isn’t a new idea, classical water cooling uses cold plates on the outside of the package, so they aren’t as efficient as the Georgia Tech method. By putting the water right at the source of the heat, packaging can be made smaller and it may even be possible to stack multiple chips without causing thermal management problems.
Higher speeds are only part of the story. Cooler electronics have less current leakage and longer device lives. Although the researchers were working with an FPGA, the technology is applicable to any integrated circuit that needs to get rid of heat. The research appears in a paper delivered at the 2015 IEEE Custom Integrated Circuit Conference.
Decapsulating ICs isn’t that hard, although removing the back part of the leadframe could be a problem. We have to wonder if an enterprising hacker will come up with a way to duplicate the feat in a garage, or–at least–something similar. After all, we’ve seen a water-cooled Raspberry Pi and LN2-cooled Arduinos.
By the way, if you are into PC overclocking, water is too mainstream. Even LN2 is too warm and the serious crowd is using liquid helium (see video below).
Photo credit: [Rob Felt]