Conductive structures in features of an insulator layer on a substrate are fabricated by a particular process. In this process, a layer of conductive material is applied over the insulator layer so that the layer of conductive material covers field regions adjacent the features and fills in the features themselves. A grain size differential between the conductive material which covers the field regions and the conductive material which fills in the features is then established by annealing the layer of conductive material. Excess conductive material is then removed to uncover the field regions and leave the conductive structures. The layer of conductive material is applied so as to define a first layer thickness over the field regions and a second layer thickness in and over the features. These thicknesses are dimensioned such that d1≦0.5d2, with d1 being the first layer thickness and d2 being the second layer thickness. Preferably, the first and second layer thicknesses are dimensioned such that d1≦0.3d2.