A formed article includes a metal particle which has a particle size in a range from 1 m to 20 m and consists of an outer shell and a core part. The core part contains Sn or a Sn alloy. The outer shell contains an intermetallic compound of Sn and Cu and covers 50% or more of a total surface area of the core part.

An electro-conductive paste includes a metal particle and a vehicle in which the metal particle is dispersed. The metal particle has a particle size in a range from 1 m to 20 m and consists of an outer shell and a core part. The core part contains Sn or a Sn alloy. The outer shell contains an intermetallic compound of Sn and Cu and covers 50% or more of a total surface area of the core part.

Apparatuses, systems, and methods associated with spacer elements for maintaining a distance between a substrate and component during reflow are disclosed herein. In embodiments, a substrate assembly may include a substrate and a component. The component may be coupled to the substrate via a solder joint, wherein the solder joint may include a spacer element and solder, the spacer element to maintain a distance between the substrate and the component. Other embodiments may be described and/or claimed.

A semiconductor package includes a processor die (e.g., an SoC) and one or more memory die (e.g., DRAM) coupled to a ball grid array (BGA) substrate. The processor die and the memory die are coupled to opposite sides of the BGA substrate using terminals (e.g., solder balls). The package may be coupled to a printed circuit board (PCB) using one or more terminals positioned around the perimeter of the processor die. The PCB may include a recess with at least part of the processor die being positioned in the recess. Positioning at least part of the processor die in the recess reduces the overall height of the semiconductor package assembly. A voltage regulator may also be coupled to the BGA substrate on the same side as the processor die with at least part of the voltage regulator being positioned in the recess a few millimeters from the processor die.

A bonding material disclosed in this specification contains high melting point metal particles, low melting point metal particles, and a thermosetting flux resin. A mass proportion of the high melting point metal particles with respect to a total mass of the high melting point metal particles and the low melting point metal particles is 55% to 75%.

A Cu core ball is provided that prevents any soft errors and decreases any connection failure. The Cu core ball includes a solder plating film formed on the surface of a Cu ball that is a Sn solder plating film or is made of a lead-free solder alloy, a principal ingredient of which is Sn. The solder plating film contains U of 5 ppb or less and Th of 5 ppb or less. The Cu ball has a purity of not less than 99.9% Cu and not more than 99.995% Cu. Pb and/or Bi contents therein are at a total of 1 ppm or more. The sphericity thereof is 0.95 or more. The obtained Cu core ball has an dose of 0.0200 cph/cm.sup.2 or less.

A Cu core ball is provided that prevents any soft errors and decreases any connection failure. The Cu core ball includes a solder plating film formed on the surface of a Cu ball that is a Sn solder plating film or is made of a lead-free solder alloy, a principal ingredient of which is Sn. The solder plating film contains U of 5 ppb or less and Th of 5 ppb or less. The Cu ball has a purity of not less than 99.9% Cu and not more than 99.995% Cu. Pb and/or Bi contents therein are at a total of 1 ppm or more. The sphericity thereof is 0.95 or more. The obtained Cu core ball has an dose of 0.0200 cph/cm.sup.2 or less.

An electro-conductive paste includes a metal particle and a vehicle in which the metal particle is dispersed. The metal particle has a particle size in a range from 1 m to 20 m and consists of an outer shell and a core part. The core part contains Sn or a Sn alloy. The outer shell contains an intermetallic compound of Sn and Cu and covers 50% or more of a total surface area of the core part.

A formed article includes a metal particle which has a particle size in a range from 1 m to 20 m and consists of an outer shell and a core part. The core part contains Sn or a Sn alloy. The outer shell contains an intermetallic compound of Sn and Cu and covers 50% or more of a total surface area of the core part.

Aiming at providing a metal particle, an electro-conductive paste, a formed article, and a laminated article that are able to form a highly reliable and high-quality electric interconnect, an electro-conductive bonding portion, or a three-dimensional structure that is less likely to produce the Kirkendall void, this invention discloses a metal particle which include an outer shell and a core part, the outer shell including an intermetallic compound and covering the core part.