A method of filling a plurality of trenches etched in a substrate. In one embodiment
the method includes depositing a layer of spin-on glass material over the substrate
and into the plurality of trenches; exposing the layer of spin-on glass material
to a solvent; curing the layer of spin-on glass material; and depositing a layer
of silica glass over the cured spin-on glass layer using a chemical vapor deposition technique.