As microprocessor power density grows and new chip packaging solutions such as 3D stacked chips become prevalent, managing the heat they generate becomes increasingly difficult.
Existing solutions to chip cooling either lack the ability to remove enough heat – risking temperatures too high to allow effective and reliable operation – or they lack the ability to precisely target hot spots. As multi-core technologies proliferate, this capability is increasingly required.
HP researchers found a solution in HP’s thermal inkjet heads, which spray ink from hundreds of tiny nozzles. Each nozzle can be individually controlled, determining both how much ink is dispensed and where it lands on the page.
By reconfiguring inkjet heads to spray tiny droplets of liquid coolant instead of ink, researchers were able to locally distribute cooling fluid on a microprocessor die. Using this technology, they demonstrated heat transfer rates of over 4000 W/cm2, which is significantly higher than all other methods.
HP Labs has an ongoing research collaboration with Santa Clara University to explore the fundamentals of this technology.