An integrated circuit comprising: • a first layer; • a first clock line for carrying a first clock signal; • a second clock line for carrying a second clock signal, the second clock line running alongside the first clock line for a distance; and • a shield structure comprising a shield wall extending from the first layer, the shield wall running between the first and second clock lines (602a, 602b) for at least a portion of the distance, • wherein the shield structure further comprises a shield cage extending from the first layer and surrounding the first and second clock lines (602a, 602b) for at least a same or different portion of the distance, the shield cage having defined therein a plurality of openings, • wherein the shield cage comprises a first side wall and a second side wall forming together two side walls, the two side walls extending from the first layer, each side wall being positioned alongside a respective one of the first and second clock lines (602a, 602b), and comprises an upper wall extending between the side walls and over both, the first and second clock lines (602a, 602b), and wherein the plurality of openings is defined in at least the upper wall, • wherein the plurality of openings is further defined in the side walls, wherein openings among the plurality of openings are defined in the first side wall among the two side walls and further openings among the plurality of openings are defined in the second side wall among the two side walls, and the openings in the first side wall are staggered with respect to the further openings defined in the second side wall to avoid any direct line-of-sight through both, the first side wall and the second side wall. • a first layer; • a first clock line for carrying a first clock signal; • a second clock line for carrying a second clock signal, the second clock line running alongside the first clock line for a distance; and • a shield structure comprising a shield wall extending from the first layer, the shield wall running between the first and second clock lines (602a, 602b) for at least a portion of the distance, • wherein the shield structure further comprises a shield cage extending from the first layer and surrounding the first and second clock lines (602a, 602b) for at least a same or different portion of the distance, the shield cage having defined therein a plurality of openings, • wherein the shield cage comprises a first side wall and a second side wall forming together two side walls, the two side walls extending from the first layer, each side wall being positioned alongside a respective one of the first and second clock lines (602a, 602b), and comprises an upper wall extending between the side walls and over both, the first and second clock lines (602a, 602b), and wherein the plurality of openings is defined in at least the upper wall, • wherein the plurality of openings is further defined in the side walls, wherein openings among the plurality of openings are defined in the first side wall among the two side walls and further openings among the plurality of openings are defined in the second side wall among the two side walls, and the openings in the first side wall are staggered with respect to the further openings defined in the second side wall to avoid any direct line-of-sight through both, the first side wall and the second side wall.