A method includes forming a dielectric layer over a carrier, forming a plurality of bond pads in the dielectric layer, and performing a planarization to level top surfaces of the dielectric layer and the plurality of bond pads with each other. A device die is bonded to the dielectric layer and portions of the plurality of bond pads through hybrid bonding. The device die is encapsulated in an encapsulating material. The carrier is then demounted from the device die and the dielectric layer.

Method for forming a semiconductor device structure is provided. The semiconductor device structure includes a first semiconductor wafer and a second semiconductor wafer bonded via a hybrid bonding structure, and the hybrid bonding structure includes a first conductive material embedded in a first polymer material and a second conductive material embedded in a second polymer material. The first conductive material is bonded to the second conductive material and the first polymer material is bonded to the second polymer material. The semiconductor device also includes at least one through silicon via (TSV) extending from a bottom surface of the first semiconductor wafer to a metallization structure of the first semiconductor wafer. The semiconductor device structure also includes an interconnect structure formed over the bottom surface of the first semiconductor wafer, and the interconnect structure is electrically connected to the metallization structure via the TSV.

A stacking structure including a first die, a second die stacked on the first die, and a third die and a fourth die disposed on the second die. The first die has a first metallization structure, and the first metallization structure includes first through die vias. The second die has a second metallization structure, and second metallization structure includes second through die vias. The first through die vias are bonded with the second through die vias, and sizes of the first through die vias are different from sizes of the second through die vias. The third and fourth dies are disposed side-by-side and are bonded with the second through die vias.

Devices and techniques including process steps make use of recesses in conductive interconnect structures to form reliable low temperature metallic bonds. A fill layer is deposited into the recesses prior to bonding. First conductive interconnect structures are bonded at ambient temperatures to second metallic interconnect structures using direct bonding techniques, with the fill layers in the recesses in one or both of the first and second interconnect structures.

Stacked semiconductor assemblies, and related systems and methods, are disclosed herein. A representative stacked semiconductor assembly can include a lowermost die and two or more modules carried by an upper surface of the lowermost die. Each of the module(s) can include a base die and one or more upper dies and/or an uppermost die carried by the base die. Each of the dies in the module is coupled via hybrid bonds between adjacent dies. Further, the base die in a lowermost module is coupled to the lowermost die by hybrid bonds. As a result of the modular construction, the lowermost die can have a first longitudinal footprint, the base die in each of the module(s) can have a second longitudinal footprint smaller than the first longitudinal footprint, and each of the upper die(s) and/or the uppermost die can have a third longitudinal footprint smaller than the second longitudinal footprint.

A Cu.sub.3Sn electrical interconnect and method of making same in an electrical device, such as for hybrid bond 3D-integration of the electrical device with one or more other electrical devices. The method of forming the Cu.sub.3Sn electrical interconnect includes: depositing a Sn layer in the via hole; depositing a Cu layer atop and in contact with the Sn layer; and heating the Sn layer and the Cu layer such that the Sn and Cu layers diffuse together to form a Cu.sub.3Sn interconnect in the via hole. During the heating, a diffusion front between the Sn and Cu layers moves in a direction toward the Cu layer as initially deposited, such that any remaining Cu layer or any voids formed during the diffusion are at an upper region of the formed Cu.sub.3Sn interconnect in the via hole, thereby allowing such voids or remaining material to be easily removed.

A semiconductor package is provided in which a first insulating layer includes a first recess spaced apart from a first pad in a first direction, and a second insulating layer includes a second recess spaced apart from a second pad in the first direction and overlapping at least a portion of the first recess in a second direction, perpendicular to the first direction, to provide an air gap together with the first recess. The semiconductor package further includes a first bonding surface defined by the first and second insulating layers contacting each other on one side of the air gap, adjacent to the first and second pads, and a second bonding surface defined by the first and second insulating layers contacting each other on another side of the air gap, opposite to the one side.

Stacked semiconductor assemblies, and related systems and methods, are disclosed herein. A representative stacked semiconductor assembly can include a lowermost die and two or more modules carried by an upper surface of the lowermost die. Each of the module(s) can include a base die and one or more upper dies and/or an uppermost die carried by the base die. Each of the dies in the module is coupled via hybrid bonds between adjacent dies. Further, the base die in a lowermost module is coupled to the lowermost die by hybrid bonds. As a result of the modular construction, the lowermost die can have a first longitudinal footprint, the base die in each of the module(s) can have a second longitudinal footprint smaller than the first longitudinal footprint, and each of the upper die(s) and/or the uppermost die can have a third longitudinal footprint smaller than the second longitudinal footprint.