Ultralow dielectric cross-linked silica aerogel nanocomposite films for interconnect technology

An increase in resistance and capacitance (RC) delay has been a critical issue in reducing integrated circuit scales. The delay is successfully reduced using low dielectric constant (κ) interconnects and porous low-κ materials adopted in real devices. However, an increase in porosity could lower κ values with a dramatic decrease in elastic modulus, which would not sustain the stress during the packaging process. Highly porous cross-linked silica aerogel thin film with an ultralow-κ value of 1.7 applied to nanodevice interconnect technology has been suggested. Cross-linking using an epoxide ring-opening reaction produced a high elastic modulus (> 5.1 GPa), stable enough to sustain the chemical mechanical polishing (CMP) and the plasma dry etching process. The thickness of aerogel films is approximately 700 nm with a hydrophobic surface. Closed-surface pores created by selective solvent evaporation can prevent metal penetration. Our cross-linked aerogel films are the first among the low-dielectric aerogel films validated as interlayer low-dielectric materials and robust candidates for ultralow -κ dielectric materials.