Carbon nanotubes to cool electronics
Desktop computers use fans to cool electronic components. Miniaturising electronic circuits while increasing functionality requires use of integrated thermal management technologies directly on individual silicon chips, ceramics and organic laminates. Thermal management is thus a critical enabling technology and EU-funded scientists working on the project 'Thermal management with carbon nanotube architectures' (THEMA-CNT) set out to make sure the EU will have an advantage over American and Asian competitors. THEMA-CNT developed cooling technology from carbon nanotube architectures and post-mounted them on silicon chips/wafers and ceramic packages. In some cases, the carbon nanotubes were even grown directly on the substrates. The technology is thus directly compatible with conventional silicon fabrication and micromodule packaging technologies making it easy and inexpensive to commercialise. Thermal management becomes even more complex and important in three-dimensional (3D) stacking of silicon wafers and integrated circuits. 3D integration is the way of the future for greater density and functionality in smaller packages with shorter connection lengths. THEMA-CNT’s innovative cooling technology was demonstrated in such stacked, 3D systems (through-silicon vias or TSVs) in which vertical interconnect access (via) passes completely through a silicon wafer. Copper-filled vias are not feasible because copper expansion is greater than the surrounding silicon for the same amount of heat. This causes mechanical problems and even breakage that can be resolved with the use of carbon nanotubes instead of copper. Scientist also studied the health and safety of carbon nanotubes contained within thermally conductive adhesives for consumer products. They found no increase in carbon nanotube exposure compared to control, confirming the safety of the test samples prepared by the consortium. Thermal management is one of the most critical issues for today’s and tomorrow’s high-performance electronic devices. The cost-effective nanotube-based cooling devices developed within THEMA-CNT have enormous market potential. This could place the EU at the forefront of an important research and technology development area.
Keywords
Electronic, thermal management, carbon nanotubes, silicon, vias, copper
