Influence of the UV Cure on Advanced Plasma Enhanced Chemical Vapour Deposition Low-k Materials

Abstract

In a recent study, low-k thin films with low dielectric constant (≤2.1) and high Young's modulus (>5 GPa) were obtained by introducing a remote plasma step between the traditional plasma enhanced chemical vapour deposition and UV curing. This study shows that the UV curing step with a narrow band lamp with wavelength of 172 nm induced more network Si–O and Si–H bonds and more densification than the curing step with a broadband lamp with wavelengths higher than 200 nm. As a consequence, the dielectric constant of the narrow band cured film was slightly higher, but Young's modulus and hardness were much improved. Electrical characterization showed good breakdown voltages and a more than sufficient time dependent dielectric breakdown reliability. The broadband lamp was then used to form thicker films which retained very well the characteristics of the thin films.