As semiconductors become more powerful, the amount of heat they generate has increased significantly. Chips just an eighth of an inch square will soon emit as much heat as a 100-watt light bulb.
Existing methods of spray cooling chips are prone to "pooling," with residual liquid left on the chip. This liquid forms an insulating vapor bubble, causing chips to overheat and malfunction.
Future chips with multiple functionalities on a single chip will have some areas of high heat, low heat and no heat. Targeted spray cooling is essential to avoid pooling. HP Labs scientists invented a method of using HP's inkjet printing technology, inkjet heads, to target coolant spray to precise areas of the chip.
The mechanism sprays a measured amount of dielectric liquid coolant onto the chip according to its heat level. The device controls the distribution, flow-rate and velocity of the liquid in much the same way inkjet printers control the placement of ink on a printed page.
The liquid vaporizes on impact, cooling the chip, and the vapor is then passed through a heat exchanger and pumped back into a reservoir that feeds the spray device.
This video
shows that technology in action. Initially, the coolant spray
(which appears here as opaque waves) is directed at the entire
chip. Then the spray pinpoints each quadrant of the chip.
Some pooling is evident here only because the chip is not
heated, so the liquid cannot evaporate.
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printable version
