Thermal Interface Materials Based on Vertically Aligned Carbon Nanotube Arrays: A Review

As the feature size of integrated circuit devices is shrinking to sub-7 nm node, the chip power dissipation significantly increases and mainly converted to the heat. Vertically Aligned Carbon Nanotube arrays (VACNTs) have a large number of outstanding properties, such as high axial thermal conductivity, low expansion coefficient, light-weight, anti-aging, and anti-oxidation. With a dramatic increment of chip temperature, VACNTs and their composites will be the promising materials as Thermal Interface Materials (TIMs), especially due to their high thermal conductivity. In this review, the synthesis, transfer and potential applications of VACNTs have been mentioned. Thermal Chemical Vapor Deposition (TCVD) has been selected for the synthesis of millimeter-scale VACNTs. After that, they are generally transferred to the target substrate for the application of TIMs in the electronics industry, using the solder transfer method. Besides, the preparation and potential applications of VACNTs-based composites are also summarized. The gaps of VACNTs are filled by the metals or polymers to replace the low thermal conductivity in the air and make them free-standing composites films. Compared with VACNTs- metal composites, VACNTs-polymer composites will be more suitable for the next generation TIMs, due to their lightweight, low density and good mechanical properties.