A metallization and bonding approach for high performance carbon nanotube thermal interface materials

A method has been developed to create vertically aligned carbon nanotube (VACNT) thermal interface materials that can be attached to a variety of metallized surfaces. VACNT films were grown on Si substrates using standard CVD processing followed by metallization using Ti/Au. The coated CNTs were then bonded to metallized substrates at 220 degrees C. By reducing the adhesion of the VACNTs to the growth substrate during synthesis, the CNTs can be completely transferred from the Si growth substrate and used as a die attachment material for electronic components. Thermal resistance measurements using a photoacoustic technique showed thermal resistances as low as 1.7 mm(2) KW-1 for bonded VACNT films 25-30 mu m in length and 10 mm(2) KW-1 for CNTs up to 130 mu m in length. Tensile testing demonstrated a die attachment strength of 40 N cm(-2) at room temperature. Overall, these metallized and bonded VACNT films demonstrate properties which are promising for next-generation thermal interface material applications.