In the manufacturing of chips, the biggest problem possed by the process in the generation of excessive heat and its dissipation. However, recently at the VLSI symposium, the Taiwanese Semiconductor Manufacturing Company presented its investigations into on-chip water-cooling to battle issues with heat dissipation. The process investigated by TSMC involves integrating water channels straight into the chip’s design.
When the transistors in the manufacturing process get increasingly compressed together due to denser manufacturing technologies and then when the vertical 3D chip stack is added, the temperature becomes an increasingly critical problem that is hard to handle. But, TSMC’s team of researchers have proposed a solution by allowing water to flow in-between sandwiched circuits. The solution is pretty simple in theory and works extremely well, but is an extremely difficult engineering feat to pull off safely.
TSMC reported having carried out testing on a dummy semiconductor which was a Thermal Test Vehicle (TTV). It was essentially a heating element made out of copper and the experiment took place in controlled lab conditions. TSMC tested three types of silicon water channel integration in controlled conditions which were that it used a pillar-based channel, in which water flowed around active semiconductor pillars to cool them down. The second was a design that featured a trench design. And finally, it tested a flatwater channel on top of the rest of the silicon chip.
The chip manufacturer further tested three types of water cooling designs. The first one was direct water cooling (DWC), the second design was with water channels being etched into their silicon layer on top of the chip proper, and finally, a design that swapped the OX layer for a cheaper liquid metal solution.
The company then reported that the best solution and by far the best was the direct water cooling method. It allows to dissipate up to 2.6 kW of heat and offered a temperature delta of 63 ºC. the OX TIM-based one, which dissipated up to 2.3 kW of heat and offered a temperature delta of 83 ºC, was termed as the second best.
However, even if the investigation offers a specific solution, it will still take years until such exotic cooling solutions are adopted in the mainstream. But this is one of the ways forward to enable continued increases in transistor density. Let’s see how the engineers of TSMC works on this new design.
