Dielectric anisotropy in the integration of Cu–SiLK™ system

As device density and performance continue to improve, low dielectric constant (k) materials are needed for interlevel dielectric (ILD) applications. The dielectric anisotropy of polymers with low k is an important property to consider for developing ILD. This is on-going research on the integration aspects of Cu–SiLK™ system. In this study, the dielectric anisotropy of SiLK polymer was evaluated with two test structures: the metal–insulator–metal (MIM) parallel capacitor structure for the out-of-phase dielectric constant (k⊥) and comb-and-serpentine interdigitated structure for the in-plane dielectric constant (k∥). A k⊥ of 2.65, a k∥ of 2.75, and a dielectric anisotropy of 3.77% were obtained for SiLK. However, SiLK exhibits larger leakage current as compared to amorphous SiO2 films. The reliability issue on the integration of Cu–SiLK is discussed.