A semiconductor device includes a solder bump overlying and electrically connected to a pad region, and a metal cap layer formed on at least a portion of the solder bump. The metal cap layer has a melting temperature greater than the melting temperature of the solder bump.

Semiconductor die assemblies having interconnect structures with redundant electrical connectors are disclosed herein. In one embodiment, a semiconductor die assembly includes a first semiconductor die, a second semiconductor die, and an interconnect structure between the first and the second semiconductor dies. The interconnect structure includes a first conductive film coupled to the first semiconductor die and a second conductive film coupled to the second semiconductor die. The interconnect structure further includes a plurality of redundant electrical connectors extending between the first and second conductive films and electrically coupled to one another via the first conductive film.

A technique for fabricating a bump structure is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared, in which the pads includes first conductive material. A metallic adhesion layer is coated on each pad. A bump base is formed on each pad by sintering conductive particles using a mold layer, in which the conductive particles includes second conductive material different from the first conductive material.

A pillar bump structure, and a method for forming the same includes forming, on a semiconductor substrate, a blanket liner followed by a seed layer including a noble metal. A first photoresist layer is formed directly above the seed layer followed by the formation of a first plurality of openings within the photoresist layer. A first conductive material is deposited within each of the first plurality of openings to form first pillar bumps. The first photoresist layer is removed from the semiconductor structure followed by removal of portions of the seed layer extending outward from the first pillar bumps, a portion of the seed layer remains underneath the first pillar bumps.

Semiconductor die assemblies having interconnect structures with redundant electrical connectors are disclosed herein. In one embodiment, a semiconductor die assembly includes a first semiconductor die, a second semiconductor die, and an interconnect structure between the first and the second semiconductor dies. The interconnect structure includes a first conductive film coupled to the first semiconductor die and a second conductive film coupled to the second semiconductor die. The interconnect structure further includes a plurality of redundant electrical connectors extending between the first and second conductive films and electrically coupled to one another via the first conductive film.

A technique for fabricating bumps on a substrate is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared. A bump base is formed on each pad of the substrate. Each bump base has a tip extending outwardly from the corresponding pad. A resist layer is patterned on the substrate to have a set of holes through the resist layer. Each hole is aligned with the corresponding pad and having space configured to surround the tip of the bump base formed on the corresponding pad. The set of the holes in the resist layer is filled with conductive material to form a set of bumps on the substrate. The resist layer is stripped from the substrate with leaving the set of the bumps.

A semiconductor device includes a conductive pattern disposed over a semiconductor substrate, and an interconnect structure disposed over the conductive pattern. The semiconductor device also includes an interconnect liner formed between the interconnect structure and the conductive pattern and surrounding the interconnect structure. The inner sidewall surfaces of the interconnect liner are in direct contact with the interconnect structure, and a maximum distance between outer sidewall surfaces of the interconnect liner is greater than a width of the conductive pattern. The semiconductor device further includes a semiconductor die bonded to the semiconductor substrate. The semiconductor die includes a conductive pad facing the interconnect structure, wherein the conductive pad is electrically connected to the conductive pattern.

A semiconductor device assembly, comprising a first semiconductor device including a first substrate with a frontside surface, a plurality of solder bumps located on the frontside surface of the first substrate, and a first polymer layer on the frontside surface. The semiconductor device assembly also comprises a second semiconductor device including a second substrate with a backside surface, a plurality of TSVs protruding from the backside surface of the second substrate, and a second polymer layer on the backside surface of the first substrate, the second polymer layer having a plurality of openings corresponding to the plurality of TSVs. The first and second semiconductor devices are bonded such that the first polymer layer contacts the second polymer layer and each of the plurality of solder bumps extends into a corresponding one of the plurality of openings and contacts a corresponding one of the plurality of TSVs.

A semiconductor device assembly, comprising a first semiconductor device including a first substrate with a frontside surface, a plurality of solder bumps located on the frontside surface of the first substrate, and a first polymer layer on the frontside surface. The semiconductor device assembly also comprises a second semiconductor device including a second substrate with a backside surface, a plurality of TSVs protruding from the backside surface of the second substrate, and a second polymer layer on the backside surface of the first substrate, the second polymer layer having a plurality of openings corresponding to the plurality of TSVs. The first and second semiconductor devices are bonded such that the first polymer layer contacts the second polymer layer and each of the plurality of solder bumps extends into a corresponding one of the plurality of openings and contacts a corresponding one of the plurality of TSVs.

A package comprises a die and a redistribution layer coupled to the die. The redistribution layer comprises a metal layer, a brass layer abutting the metal layer, and a polymer layer abutting the brass layer. The package is a wafer chip scale package (WCSP). The package further includes a solder ball attached to the redistribution layer.