Via and plug architectures for integrated circuit interconnects and methods of manufacture

Methods and architectures for forming metal line plugs that define separations between two metal line ends, and for forming vias that interconnect the metal lines to an underlying contact. The line plugs are present in-plane with the metal lines while vias connecting the lines are in an underlying plane. One lithographic plate or reticle that prints lines at a given pitch (P) may be employed multiple times, for example each time with a pitch halving (P/2), or pitch quartering (P/4) patterning technique, to define both metal line ends and metal line vias. A one-dimensional (1D) grating mask may be employed in conjunction with cross-grating (orthogonal) masking structures that are likewise amenable to pitch splitting techniques.