A pre-soldered circuit carrier includes a carrier having a metal die attach surface, a plated solder region on the metal die attach surface, wherein a maximum thickness of the plated solder region is at most 50 ?m, the plated solder region has a lower melting point than the first bond pad, and the plated solder region forms one or more intermetallic phases with the die attach surface at a soldering temperature that is above the melting point of the plated solder region.

Certain examples disclosed herein are directed to materials that are designed for use in interconnects of electrical devices such as, for example, printed circuit boards and solar cells. In certain examples, a two-step solder may be used to reduce stresses on the materials used in the production of the electrical devices.

Embodiments of the present disclosure are directed to a leadframe package with recesses formed in outer surface of the leads. The recesses are filled with a filler material, such as solder. The filler material in the recesses provides a wetable surface for filler material, such as solder, to adhere to during mounting of the package to another device, such as a printed circuit board (PCB). This enables strong solder joints between the leads of the package and the PCB. It also enables improved visual inspection of the solder joints after the package has been mounted.

A dual solder layer for fluidic self assembly, an electrical component substrate, and method employing same is described. The dual solder layer comprises a layer of a self-assembly solder disposed on a layer of a base solder which is disposed on the solder pad of an electrical component substrate. The self-assembly solder has a liquidus temperature less than a first temperature and the base solder has a solidus temperature greater than the first temperature. The self-assembly solder liquefies at the first temperature during a fluidic self assembly method to cause electrical components to adhere to the substrate. After attachment, the substrate is removed from the bath and heated so that the base solder and self-assembly solder combine to form a composite alloy which forms the final electrical solder connection between the component and the solder pad on the substrate.

An embodiment composite material for semiconductor package mount applications may include a first component including a tin-silver-copper alloy and a second component including a tin-bismuth alloy or a tin-indium alloy. The composite material may form a reflowed bonding material having a room temperature tensile strength in a range from 80 MPa to 100 MPa when subjected to a reflow process. The reflowed bonding material may include a weight fraction of bismuth that is in a range from approximately 4% to approximately 15%. The reflowed bonding material may an alloy that is solid solution strengthened by a presence of bismuth or indium that is dissolved within the reflowed bonding material or a solid solution phase that includes a minor component of bismuth dissolved within a major component of tin. In some embodiments, the reflowed bonding material may include intermetallic compounds formed as precipitates such as Ag.sub.3Sn and/or Cu.sub.6Sn.sub.5.

A pre-soldered circuit carrier includes a carrier having a metal die attach surface, a plated solder region on the metal die attach surface, wherein a maximum thickness of the plated solder region is at most 50 m, the plated solder region has a lower melting point than the first bond pad, and the plated solder region forms one or more intermetallic phases with the die attach surface at a soldering temperature that is above the melting point of the plated solder region.

A mounting structure includes a bonding material (106) that bonds second electrodes (104) of a circuit board (105) and bumps (103) of a semiconductor package (101), the bonding material (106) being surrounded by a first reinforcing resin (107). Moreover, a portion between the outer periphery of the semiconductor package (101) and the circuit board (105) is covered with a second reinforcing resin (108). Even if the bonding material (106) is a solder material having a lower melting point than a conventional bonding material, high drop resistance is obtained.

When soldering a package having an electrode on which Ni/Au or AgPd alloy is plated, to a printed circuit board having a Cu electrode or an electrode on which Cu is plated, a solid-phase diffusion layer is formed within a layered solder material for bonding different species of electrodes. The layered solder material is composed of a solder material of SnAgCu series or SnSb series and a solder material of SnAgCuNi series or SnPb series. The electrode on which Ni/Au or AgPd alloy is plated and the Cu electrode or the electrode on which Cu is plated are soldered with the solder material of SnAgCu series or SnSb series being attached to the Cu electrode and the solder material of SnAgCuNi series or SnCu series being attached to the electrode on which Ni/Au or AgPd alloy is plated. This restrains formation of intermetallic compounds and provides high bonding reliability.

Embodiments of the present disclosure are directed to a leadframe package with recesses formed in outer surface of the leads. The recesses are filled with a filler material, such as solder. The filler material in the recesses provides a wetable surface for filler material, such as solder, to adhere to during mounting of the package to another device, such as a printed circuit board (PCB). This enables strong solder joints between the leads of the package and the PCB. It also enables improved visual inspection of the solder joints after the package has been mounted.

Embodiments of the present disclosure are directed to a leadframe package with recesses formed in outer surface of the leads. The recesses are filled with a filler material, such as solder. The filler material in the recesses provides a wetable surface for filler material, such as solder, to adhere to during mounting of the package to another device, such as a printed circuit board (PCB). This enables strong solder joints between the leads of the package and the PCB. It also enables improved visual inspection of the solder joints after the package has been mounted.