Integrated circuit devices are fabricated by fabricating a conductive line on an insulating layer on an integrated circuit substrate. The conductive line includes a bottom adjacent the insulating layer, a top remote from the insulating layer and first and second sidewalls therebetween. An insulating spacer is formed to extend along the first and second sidewalls and to also extend along at least a portion of the bottom between the conductive line and the insulating layer. By providing an insulating spacer beneath at least a portion of the conductive line, insulation reliability may be improved even as the spacer may become narrower and/or the contact area may be enlarged.