An integrated circuit includes a device, a first interconnect structure disposed above the device and a second interconnect structure positioned below the device. The first interconnect structure includes multiple frontside metal layers. The second interconnect structure includes multiple backside metal layers, where each backside metal layer includes metal conductors routed according to diagonal routing. In some embodiments, a backside interconnect structure can include another backside metal layer that includes metal conductors routed according to mixed-Manhattan-diagonal routing. A variety of techniques can be used to route signals between metal conductors in the backside interconnect structure and cells on one or more frontside metal layers.