A protection layer is coated or otherwise formed over the interconnect structure. The interconnect structure includes a metal line (such as top and bottom metal layers connected by a metal via) and a low-K material. The protection layer includes a vertically aligned dielectric or other material dispersed with carbon nanotubes. The protection layer could include one or multiple layers of carbon nanotubes, and the carbon nanotubes could have any suitable dispersion, alignment, and pattern in each layer of the protection layer. Among other things, the carbon nanotubes help to reduce or prevent damage to the interconnect structure, such as by reducing or preventing the collapse of the low-K material or delamination between the metal line and the low-K material.