A method of manufacturing a semiconductor device having a low-k dielectric layer is provided. An embodiment comprises forming a dielectric layer on a substrate, wherein the layer comprises a pore generating material dispersed in an uncured matrix. A second step comprises forming pores in the uncured matrix by irradiating the layer with radiation having a first wavelength. After pore forming, a third step comprises cross-linking the dielectric by irradiating it at a second wavelength, the second being less than the first. In an embodiment, the irradiating wavelengths comprise ultra-violet radiation. Embodiments may further include repairing processing damage wherein the damage includes dangling bonds or silanol formation. The repairing includes annealing in a carbon-containing ambient such as C2H4, C3H6, or hexamethyldisilazane (HMDS).