Abstract: A method of forming a semiconductor structure includes providing a stack structure having a first side and a second side opposite the first side. The stack structure includes a bottom wafer comprising a substrate; a plurality of through-silicon vias in the substrate; and a plurality of under bump metallurgies (UBMs) connected to the plurality of through-silicon vias, wherein the UBMs are on the first side of the stack structure. The method further includes attaching a handling wafer on the second side of the stack structure; performing a chip probing process; and removing the handling wafer from the stack structure.

Abstract: A semiconductor die including a test structure is provided. The semiconductor die includes a loop-back formed on a surface of the semiconductor die. The loop-back structure includes a first bonding pad on a first surface; and a second bonding pad on the first surface, wherein the first and the second bonding pads are electrically disconnected from integrated circuit devices in the semiconductor die. A conductive feature electrically shorts the first and the second bonding pads. An additional die including an interconnect structure is bonded onto the semiconductor die. The interconnect structure includes a third and a fourth bonding pad bonded to the first and the second bonding pads, respectively. Through-wafer vias in the additional die are further connected to the third and fourth bonding pads.

Abstract: A semiconductor die including a test structure is provided. The semiconductor die includes a loop-back formed on a surface of the semiconductor die. The loop-back structure includes a first bonding pad on a first surface; and a second bonding pad on the first surface, wherein the first and the second bonding pads are electrically disconnected from integrated circuit devices in the semiconductor die. A conductive feature electrically shorts the first and the second bonding pads. An additional die including an interconnect structure is bonded onto the semiconductor die. The interconnect structure includes a third and a fourth bonding pad bonded to the first and the second bonding pads, respectively. Through-wafer vias in the additional die are further connected to the third and fourth bonding pads.

Abstract: A method of forming a semiconductor structure includes providing a stack structure having a first side and a second side opposite the first side. The stack structure includes a bottom wafer comprising a substrate; a plurality of through-silicon vias in the substrate; and a plurality of under bump metallurgies (UBMs) connected to the plurality of through-silicon vias, wherein the UBMs are on the first side of the stack structure. The method further includes attaching a handling wafer on the second side of the stack structure; performing a chip probing process; and removing the handling wafer from the stack structure.