Planarization of a non-conformal device layer in semiconductor fabrication

A substantially planar surface is produced from a non-conformal device layer formed over a complex topography, which includes narrow features with narrow gaps and wide features and wide gaps. A conformal layer is deposited over the non-conformal layer. The surface is then polished to expose the non-conformal layer over the wide features. An etch selective to the non-conformal layer is then used to substantially remove the non-conformal layer over the wide features. The conformal layer is then removed, exposing the non-conformal layer, The thickness of the non-conformal layer is now more uniform as compared to before. This enables the polish to produce a planar surface with reduced dishing in the wide spaces.