Advanced conventional interconnects: State of the art, future trends, and limitations

Abstract

As design rules drop below 90 nm, a variety of challenges emerge such as RC delay, electromigration resistance, and heat dissipation exacerbated by increased chip power. The use of copper and thin barrier layers solves resistivity and electromigration problems but not for long due to electron scattering issues' increasing the apparent resistivity. Moreover, reliability issue with respect to an efficient diffusion barrier is a concern. Low k dielectrics allowing capacitance reduction have low thermal conductivity and hence poor heat dissipation capability. Integration of copper and low k dielectrics is intensively studied worldwide, and this chapter gives an overview of the international state of the art to overcome critical issues of advanced interconnects. Severe limitations of the conventional interconnects in the near future act as a technology push for alternative solutions such as 3D or optical interconnects.