A bonding structure is a bonding structure which bonds a light emitting element and a substrate and includes a first electrode formed on the light emitting element, a second electrode formed on the substrate, and a bonding layer which bonds the first electrode and the second electrode, and the bonding layer contains a first bonding metal component and a second bonding metal component different from the first bonding metal component.

A solder alloy has an alloy composition consisting of, in mass %, Ag: from 3.2 to 3.8%, Cu: from 0.6 to 0.8%, Ni: from 0.01 to 0.2%, Sb: from 2 to 5.5%, Bi: from 1.5 to 5.5%, Co: from 0.001 to 0.1%, Ge: from 0.001 to 0.1%, and optionally at least one of Mg, Ti, Cr, Mn, Fe, Ga, Zr, Nb, Pd, Pt, Au, La and Ce: 0.1% or less in total, with the balance being Sn. The alloy composition satisfies the following relationship (1): 2.93{(Ge/Sn)+(Bi/Ge)}(Bi/Sn) (1). In the relationship (1), each of Sn, Ge, and Bi represents the content (mass %) in the alloy composition.

A support substrate has first electric contacts in a front face. An electronic component is located above the front face of the support substrate and has second electric contacts facing the first electric contacts of the support substrate. An electric connection structure is interposed between corresponding first and second electric contacts of the support substrate and the electronic component, respectively. Each electric connection structure is formed by: a shim that is made of a first electrically conducting material, and a coating that is made of a second electrically conducting material (different from the first electrically conducting material). The coating surrounds the shim and is in contact with the corresponding first and second electric contacts of the support substrate and the electronic component.

A solder ball according to the present invention contains 0.2 to 2.2% by mass of Zn, and a balance of Sn, and has a spherical diameter of 0.1 to 120 m and a yellowness (b*) in an L*a*b* color system of 2.70 or more and 9.52 or less. An oxide film is formed by performing aging treatment. By producing a solder ball having a yellowness of 2.70 or more and 9.52 or less, it is possible to suppress the growth of a Cu.sub.3Sn layer and/or a CuZn(Sn) layer during joining.

A solder ball includes 0.1% by mass or more and 10% by mass or less of In and a remainder of Sn. The ball has a yellowness (b*) in an L*a*b* color system of 2.8 or more and 15.0 or less and a lightness (L*) of 60 or more and 100 or less. The ball further includes at least one element selected from a group of 0% by mass or more and 4% by mass or less of Ag, 0% by mass or more and 1.0% by mass or less of Cu, 0% to 3% by mass in total of Bi and/or Sb, and 0% to 0.1% by mass in total of an element selected from a group of Ni, Co, Fe, Ge, and P, excluding a solder ball including 3% by mass of Ag, 0.5% by mass of Cu, 0.2% by mass of In and a remainder of Sn.

Provided is a solder alloy, a solder ball, a chip solder, a solder paste and a solder joint in which discoloration is suppressed and a growth of an oxide film is suppressed under a high temperature and high humidity environment. The solder alloy contains 0.005% by mass or more and 0.1% by mass or less of Mn, 0.001% by mass or more and 0.1% by mass or less of Ge and more than 0% by mass and 4% by mass or less of Ag, and a principal ingredient of remainder is Sn.

An example system for maintaining the shape of a circuit board includes metal balls that are configured not to collapse in whole or part in response to a force below a predefined force and a temperature below a predefined temperature. The metal balls are configured to support a substrate and are part of electrical connections between the substrate and a circuit board. The system includes a fixture configured to apply force to the substrate while the substrate is subjected to the temperature. The fixture is configured to distribute the force across a surface of the substrate that is not in contact with the metal balls such that the force applied by the fixture and the support of the substrate by the metal balls maintains a shape of the substrate at the temperature.

Implementations of the disclosure are directed to a thermal via filling solder paste that exhibits little to no volume loss during reflow. The solder paste may include a solder powder such as tin-silver-copper alloy, a high melting temperature powder (e.g., a copper powder) having a higher melting temperature than the solder powder, and flux. The high melting temperature powder may be configured to have a melting temperature significantly higher than the solder powder. During reflow, the solder powder may melt and wet to the high melting temperature powder, forming intermetallic compounds that keep the via holes filled during and after reflow soldering.

Provided is low alpha-ray emitting bismuth having an alpha dose of 0.003 cph/cm.sup.2 or less. Additionally provided is a method of producing low alpha-ray emitting bismuth, wherein bismuth having an alpha dose of 0.5 cph/cm.sup.2 or less is used as a raw material, the raw material bismuth is melted in a nitric acid solution via electrolysis to prepare a bismuth nitrate solution having a bismuth concentration of 5 to 50 g/L and a pH of 0.0 to 0.4, the bismuth nitrate solution is passed through a column filled with ion-exchange resin to eliminate polonium contained in the solution by an ion-exchange resin, and bismuth is recovered by means of electrowinning from the solution that was passed through the ion-exchange resin. Recent semiconductor devices are of high density and high capacity, and therefore are subject to increased risk of soft errors caused by the effects of alpha rays emitted from materials in the vicinity of semiconductor chips. In particular, there is a strong demand for higher purification of solder materials used near semiconductor devices, and there is a demand for low alpha-ray emitting materials. Therefore, the present invention aims to elucidate the phenomenon of alpha ray generation from bismuth, and to provide a low alpha-ray emitting, high-purity bismuth that can be applied to the required materials and a production method thereof, as well as to provide an alloy of low alpha-ray emitting bismuth and tin and a production method thereof.

A disk having at least one electric connecting element is described. The disk has a substrate, and electrically conductive structure on a region of the substrate, a connecting element containing at least chromium-containing steel, and a layer of a soldering compound that electrically connects the connecting element to sub-regions of the electrically conductive structure.