As illustrated by the cross-sectional view 900 of FIG. 9, an interconnect structure 706 is partially formed on the first and second access transistors 304, 306. The interconnect structure 706 comprises an interconnect dielectric layer 708, a contact via 506, and a plurality of lower-level wires 508. The interconnect dielectric layer 708 comprises an interlayer dielectric (ILD) layer 708ild, and further comprises an intermetal dielectric (IMD) layer 708imd overlying the ILD layer 708ild. The contact via 506 is in the ILD layer 708ild and extends through the ILD layer 708ild to the shared source/drain region 702s. The plurality of lower-level wires 508 is in the IMD layer 708imd and comprises a composite source line 508a and a lower-level island 508b. Note that the composite source line 508a is not fully visible within the cross-sectional view 900. For a more complete view, see the top layout 500B of FIG. 5B.
