TSMC is exploring on-chip water cooling solutions

For today’s high-performance chips, heat dissipation is a thorny issue. In addition to the traditional use of air-cooled heat dissipation with additional radiators, water-cooled heat dissipation seems to be a more efficient choice. Industry giants like Microsoft even put data center servers in the sea or soak the equipment in special liquids to improve the efficiency of heat dissipation.

According to Hardwareluxx, TSMC recently demonstrated its research on on-chip water cooling at the VLSI seminar. As a new heat dissipation solution, it involves the direct integration of water channels into the chip design. Current heat dissipation solutions include direct contact with the radiator, direct chip contact technology, or immersion in a non-conductive liquid. The first two heat dissipation solutions can only dissipate heat on the direct contact surface. If the chip adopts stacking technology, heat dissipation will be more difficult.

With the increasing complexity of chip design and the development of process manufacturing technology, tighter processes, and vertical 3D chip stacking technologies have made the space between transistors more compressed, and how to solve the problem of heat dissipation has become a big problem.

Researchers at TSMC believe that the future solution is to let water flow between mezzanine circuits. It sounds simple, but it is very difficult to actually operate. At this stage, immersion in a non-conductive liquid to dissipate heat is a good way for chips using stacking technology, but it becomes very expensive in traditional usage scenarios and difficult to deploy.

For this reason, TSMC has conducted related simulation tests on three different silicon water channels. One is the direct water cooling method. The water has its own circulation channel and is directly etched into the silicon wafer of the chip.

The other is a water channel etched to the silicon layer on the top of the chip, and a thermal interface material (TIM) layer of OX (silicon oxide fusion) is used to transfer heat from the chip to the water cooling layer. Finally, it is a way to replace the thermal interface material layer with a simple and cheap liquid metal.

Of course, these strange-looking designs can’t really be used yet, and it will take several years to wait, but it will be one of the directions for solving semiconductor heat dissipation in the future.