Thermal characterization of a bridge-link carbon nanotubes array used as a thermal adhesive

A dense and vertically aligned single-walled carbon nanotube (SWCNT) array was assembled between a chip and a substrate by a fluidic assembly method. The SWCNT bridged the interface as a thermal interface material (TIM). The minimum interfacial thermal resistance was measured close to 4.5 mm2 K/W by the laser flash method. This value was lower than that of commercial thermal grease. Filling up the remaining space of the SWCNT array with a highly penetrative glue (LOCTITE®4699™, Henkel Co. Korea) was found to produce a significant increase in shear strength from 450 kPa to 3 MPa, as well as an approximate 10% decrease in thermal diffusivity. The material's higher thermal performance is expected to allow a chip to make a good connection to a heat sink in microelectronics packaging, thus acting as a substitute for conventional thermal adhesives.