A lead-free solder ball is provided which suppresses interfacial peeling in a bonding interface of a solder ball, fusion defects which develop between the solder ball and solder paste, and which can be used both with Ni electrodes plated with Au or the like and Cu electrodes having a water-soluble preflux applied atop Cu. The lead-free solder ball for electrodes of BGAs or CSPs consists of 1.6-2.9 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. It has excellent resistance to thermal fatigue and to drop impacts regardless of the type of electrodes of a printed circuit board to which it is bonded, which are Cu electrodes or Ni electrodes having Au plating or Au/Pd plating as surface treatment.

Reliability of a semiconductor device is improved. A slope is provided on a side face of an interconnection trench in sectional view in an interconnection width direction of a redistribution layer. The maximum opening width of the interconnection trench in the interconnection width direction is larger than the maximum interconnection width of the redistribution layer in the interconnection width direction, and the interconnection trench is provided so as to encapsulate the redistribution layer in plan view.

Reliability of a semiconductor device is improved. A slope is provided on a side face of an interconnection trench in sectional view in an interconnection width direction of a redistribution layer. The maximum opening width of the interconnection trench in the interconnection width direction is larger than the maximum interconnection width of the redistribution layer in the interconnection width direction, and the interconnection trench is provided so as to encapsulate the redistribution layer in plan view.

A method of forming semiconductor devices includes providing a wafer having a first side and second side, electrically conductive pads at the second side, and an electrically insulative layer at the second side with openings to the pads. The first side of the wafer is background to a desired thickness and an electrically conductive layer is deposited thereon. Nickel layers are simultaneously electrolessly deposited over the electrically conductive layer and over the pads, and diffusion barrier layers are then simultaneously deposited over the nickel layers. Another method of forming semiconductor devices includes depositing backmetal (BM) layers on the electrically conductive layer including a titanium layer, a nickel layer, and/or a silver layer. The BM layers are covered with a protective coating and a nickel layer is electrolessly deposited over the pads. A diffusion barrier layer is deposited over the nickel layer over the pads, and the protective coating is removed.

A method of forming semiconductor devices includes providing a wafer having a first side and second side, electrically conductive pads at the second side, and an electrically insulative layer at the second side with openings to the pads. The first side of the wafer is background to a desired thickness and an electrically conductive layer is deposited thereon. Nickel layers are simultaneously electrolessly deposited over the electrically conductive layer and over the pads, and diffusion barrier layers are then simultaneously deposited over the nickel layers. Another method of forming semiconductor devices includes depositing backmetal (BM) layers on the electrically conductive layer including a titanium layer, a nickel layer, and/or a silver layer. The BM layers are covered with a protective coating and a nickel layer is electrolessly deposited over the pads. A diffusion barrier layer is deposited over the nickel layer over the pads, and the protective coating is removed.

A semiconductor package that includes a conductive can, a power semiconductor device electrically and mechanically attached to the inside surface of the can, and an IC semiconductor device copackaged with the power semiconductor device inside the can.

Methods of forming a microelectronic packaging structure and associated structures formed thereby are described. Those methods may include forming a cavity in a plating material to hold a die, attaching the die in the cavity, forming a dielectric material adjacent the die, forming vias in the dielectric material adjacent the die, forming PoP lands in the vias, forming interconnects in the vias, and then removing the plating material to expose the PoP lands and die, wherein the die is disposed above the PoP lands.

Methods of forming bonded semiconductor structures include providing a first semiconductor structure including a device structure, bonding a second semiconductor structure to the first semiconductor structure below about 400° C., forming a through wafer interconnect through the second semiconductor structure and into the first semiconductor structure, and bonding a third semiconductor structure to the second semiconductor structure on a side thereof opposite the first semiconductor structure. In additional embodiments, a first semiconductor structure is provided. Ions are implanted into a second semiconductor structure. The second semiconductor structure is bonded to the first semiconductor structure. The second semiconductor structure is fractured along an ion implant plane, a through wafer interconnect is formed at least partially through the first and second semiconductor structures, and a third semiconductor structure is bonded to the second semiconductor structure on a side thereof opposite the first semiconductor structure. Bonded semiconductor structures are formed using such methods.

In some embodiments, the present disclosure relates to a package assembly having a bump on a first substrate. A molding compound is on the first substrate and contacts sidewalls of the bump. A no-flow underfill layer is on a conductive region of a second substrate. The no-flow underfill layer and the conductive region contact the bump. A mask layer is arranged on the second substrate and laterally surrounds the no-flow underfill layer. The no-flow underfill layer contacts the substrate between the conductive region and the mask layer.

In some embodiments, the present disclosure relates to a package assembly having a bump on a first substrate. A molding compound is on the first substrate and contacts sidewalls of the bump. A no-flow underfill layer is on a conductive region of a second substrate. The no-flow underfill layer and the conductive region contact the bump. A mask layer is arranged on the second substrate and laterally surrounds the no-flow underfill layer. The no-flow underfill layer contacts the substrate between the conductive region and the mask layer.