Semiconductor integrated circuit line structures for improving a process window in the vicinity of dense-to-isolated pattern transition areas and a technique to implement the line structures in the layout process are described in this disclosure. The disclosed structure includes a semiconductor substrate, and a material layer above the substrate. The material layer has a closely spaced dense line structure, an isolated line structure next to the dense line structure, and a dummy line shoulder structure formed in the vicinity of the dense line and the isolated line structures. One end of the dummy line shoulder structure connects to the isolated line structure and another end extends away from the isolated line structure in an orientation substantially perpendicular to the isolated line structure.