Provided are methods of stabilizing an underlying dielectric diffusion barrier during deposition and ultraviolet (UV) processing of an overlying dielectric layer. Methods include modulating the optical properties reduces the effects of UV radiation on the dielectric diffusion barrier layer. The dielectric diffusion barrier can be made to absorb less UV radiation. A dielectric layer with UV absorbing properties may also be added on top of the diffusion barrier layer so less UV is transmitted. Both methods result in reduced interaction between UV radiation and the dielectric diffusion barrier.