New Chip Checks Cooling For Stacked Electronics

The chip tests cooling methods for stacked microelectronics by creating heat and measuring temperature, helping researchers manage overheating in 3D chip systems.

As microelectronic systems need to become more powerful and efficient, the industry is starting to stack chips on top of each other, called 3D integration. This lets fast processors, like the ones used for artificial intelligence, sit closely with special chips for things like communication and imaging. But stacking chips creates a big problem: they can get too hot. To help solve this, MIT Lincoln Laboratory made a special chip that helps test ways to cool these chip stacks. The chip heats up like a real high-power chip would, creating hot spots and spreading heat through the silicon. As new cooling methods are used, the chip measures how much the temperature changes. By placing it inside a chip stack, researchers can better understand how heat moves through the layers and see how well different cooling ideas work.

The chip performs two key functions: generating heat and sensing temperature. To simulate the intense power demands of future high-performance chips, the team designed circuits capable of operating at extremely high power densities—on the order of kilowatts per square centimeter. They also replicated the circuit layout of real-world logic chips, making the test chip a realistic and effective stand-in for benchmarking cooling solutions.

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The chip’s heaters are designed to mimic both the background heat distributed throughout a stack and the intense localized hot spots. These hot spots often arise in the most buried and hard-to-reach areas of a 3D chip stack, making it challenging for developers to determine whether cooling methods—such as microchannels delivering cold liquid—are effectively reaching and cooling those critical regions.

That’s where the chip’s temperature-sensing elements come into play. Scattered across the chip are what Chen describes as “tiny thermometers,” which measure temperature at multiple points as cooling solutions are applied.

As the diodes heat up, their current-to-voltage ratio changes. By monitoring this change, it is possible to determine the temperature at different points on the chip, such as 200 degrees Celsius, 100 degrees Celsius, or 50 degrees Celsius. The design process involved thinking creatively about how devices could fail due to overheating, and then using those same properties to create effective temperature measurement tools.