A method of generating a layout diagram including a first level of metallization (M_1st level) including: identifying, in the layout diagram, a filler cell and a first functional cell substantially abutting the filler cell; the first functional cell including first and second side boundaries, first wiring patterns in the M_1st level, and representing corresponding first conductors in the first functional cell region; and first and second groups of cut patterns overlying corresponding portions of the first wiring patterns and being substantially aligned with the corresponding first and second side boundaries; adjusting one or more locations of corresponding one or more selected cut patterns of the second group thereby correspondingly elongating one or more selected ones of the first wiring patterns so as to be corresponding first elongated wiring patterns which extend across the second boundary of the first functional cell into the filler cell.