Bond Structure in Porous SiOCH Low-k Film Fabricated by Ultraviolet Irradiation

Abstract

Using an advanced ultraviolet irradiation (UV curing) process, a high performance porous low-k film of k=2.57, whose Young's modulus is larger than 8 GPa, now is developed to improve the mechanical properties of a film by the reconstruction of Si–O network structure from cage-like Si–O bonds, suboxide structures and Si–CH3 bonds. It was found that the UV curing process can efficiently strengthen the mechanical properties of porous low-k film, and reduce its dielectric constant value by removing hydrocarbon bonds to form porosities. As a result, the key features of this optimal SiOCH material, high elastic modulus and a low dielectric constant, provide promising properties for future integrated schemes.