Research On Key Technologies Of Carbon Nanotubes Interconnection For Integrated Circuit

As the feature size of IC shrinks, the effect of scattering of current carrying electrons at the conductor surface as well as at the grain boundaries of the conducting material causes resistance of interconnect to increase manifold. At the dimension of 30nm, the current density of interconnect would reach 10⁷A/cm². It is beyond the allowed current density of metal interconnect in current technology. A replacement material for interconnects must be developed as a result of the fatal flaw of metal interconnects. It is shown that the current carrying capacity of multi-wall carbon nanotube (MWCNT) did not degrade at 10¹⁰ A/m². Besides the large current-carrying capacity, the multi-channel quasi-ballistic conduction of MWCNT attract attention of experts in the field of IC interconnect. And Carbon Nanotubes (CNT) arrays have recently been proposed as one of the promising replacements for metal interconnects in GLSI.The effect of catalyst treatment on the growth of high density self-aligned CNT for IC interconnection was studied. Fe film and Ni film was prepared by ion beam sputter (IBS) and magnetron sputter. Then the film was treated by plasma in PECVD equipment. The effects of different ways of sputter, heating rate, and plasma power and film thickness is compared. On this basis, experiment on CNT growth by PECVD was carried out. Effects of different pressure, carbon sources and growth temperature to CNT growth were compared. The morphology and structure of catalyst and the structural properties of CNT is characterized by SEM, ATM, TEM and Raman.The main results of the research on catalyst preparation and self-aligned CNT growth can be described as followed:First, high density catalyst particles were obtained by magnetron sputter and plasma treatment. The particle size is about 100nm and CNT growth is achieved on this catalyst particles. Then higher density catalyst particles were obtained by IBS and plasma treatment. After plasma treatment, the particle size was decreased to about 20nm. Second, on the basis of high density catalyst particles, experiment on the effect of different carbon sources, pressure and growth temperature to CNT growth was performed. And self-aligned CNT growth was achieved. Besides, CNT was prepared with C2H2 as carbon source at 550℃.Finally, from the perspective of interconnect application, interconnect model, electrical properties and heat transport properties of CNT are discussed in this paper. In sum, the parameters of catalyst treatment to obtain high density self-aligned CNT were optimized, and this will be useful for the following CNT-IC interconnection research.