US Patent 10497677 ESD protection in a stacked integrated circuit assembly

An example integrated circuit (IC) assembly includes: a substrate, and a first IC die stacked on a second IC die, a stack of the first IC die and the second IC die mounted to the substrate. The first IC die includes an active side, a backside, a plurality of through-silicon vias (TSVs) exposed on the backside, an electrostatic discharge (ESD) circuit on the active side, and metallization on the active side. The metallization includes a first plurality of metal layers disposed on the active side and a second plurality of metal layers disposed on the first plurality of metal layers, each of the second plurality of metal layers thicker than each of the first plurality of metal layers. The metallization further includes a U-route that electrically couples a first TSV of the plurality of TSVs to the ESD circuit, the U-route including a conductive path through the second plurality of metal layers.