A solder paste that contains or consists of (i) 10-30% by weight of at least one type of particles that each contain a phosphorus fraction of >0 to ≦500 wt-ppm and are selected from copper particles, copper-rich copper/zinc alloy particles, and copper-rich copper/tin alloy particles, (ii) 60-80% by weight of at least one type of particles selected from tin particles, tin-rich tin/copper alloy particles, tin-rich tin/silver alloy particles, and tin-rich tin/copper/silver alloy particles, and (iii) 3-30% by weight solder flux, in which the mean particle diameter of metallic particles (i) and (ii) is ≦15 μm.

Provided is a solder material which enables a growth of an oxide film to be inhibited. A solder ball which is a solder material is composed of a solder layer and a covering layer covering the solder layer. The solder layer is spherical and is composed of a metal material containing an alloy including Sn content of 40% and more. Otherwise the solder layer is composed of a metal material including Sn content of 100%. In the covering layer, a S.sub.nO film is formed outside the solder layer, and a S.sub.nO.sub.2 film is formed outside the S.sub.nO film. A thickness of the covering layer is preferably more than 0 nm and equal to or less than 4.5 nm. Additionally, a yellow chromaticity of the solder ball is preferably equal to or less than 5.7.

A soldering alloy includes an alloy composition consisting of 13-22 mass % of In, 0.5-2.8 mass % of Ag, 0.5-5.0 mass % of Bi, 0.002-0.05 mass % of Ni, and a balance Sn. A soldering alloy, a soldering paste, a preform solder, a soldering ball, a wire solder, a resin flux cored solder and a solder joint, each of which is composed of the soldering alloy. An electronic circuit board and a multi-layer electronic circuit board joined by using the solder joint.

Provided is a solder alloy, a solder paste, a solder preform, and a solder joint which suppress chip cracking during cooling, improve the heat dissipation characteristics of the solder joint, and exhibit high joint strength at high temperatures.

The solder alloy has an alloy composition of, by mass: Sb: 9.0 to 33.0%; Ag: more than 4.0% and less than 11.0%; and Cu: more than 2.0% and less than 6.0%, with the balance of Sn.

Moreover, the solder paste, the solder preform, and the solder joint all contain said solder alloy.

Provided are metal particles for an adhesive paste, a solder paste composition including the same, and a method of preparing the metal particles for an adhesive paste. The metal particles for an adhesive paste may include a core including one or more metal materials; and a shell arranged on part or an entirety of the core and including one or more metal materials. The metal material of the core may have a melting point higher than that of the metal material of the shell. An intermetallic compound is capable of being formed between the metal material of the core and the metal material of the shell. A ratio (D90/D10) of the 90% cumulative mass particle size distribution (D90 size) to the 10% cumulative mass particle size distribution (D10 size) in a particle size distribution of the metal particles may be 1.22 or less.

A lead-free solder has a heat resistance temperature which is high and a thermal conductive property which is not changed in a high temperature range. A semiconductor device includes a solder material containing more than 5.0% by mass and 10.0% by mass or less of Sb and 2.0 to 4.0% by mass of Ag, an element selected from the group consisting of: more than 0 and 1.0% by mass or less of Si, more than 0 and 0.1% by mass or less of V, 0.001 to 0.1% by mass of Ge, 0.001 to 0.1% by mass of P, and more than 0 and 1.2% by mass or less of Cu, and the remainder consisting of Sn and inevitable impurities. A bonding layer including the solder material, is formed between a semiconductor element and a substrate electrode or a lead frame.

A semiconductor device includes an insulating substrate formed by integrating a ceramic base plate and a cooling fin; a multiple of plate interconnection members; and a plurality of semiconductor elements. The one faces of the semiconductor elements are bonded to the ceramic base plate of the insulating substrate with a chip-bottom solder, and the other faces thereof are bonded to the plate-interconnection members with a chip-top solder so that plate interconnection members correspond respectively to the semiconductor elements. The chip-bottom solder and the chip-top solder both contain mainly Sn and 0.3-3 wt. % Ag and 0.5-1 wt. % Cu. This allows the semiconductor device to be reduced in size without impairing heat dissipation.

Disclosed is a pyrometallurgical process for producing a crude solder comprising at least 9.5-69% wt of tin and at least 25% wt lead, at least 80% tin and lead together, 0.08-12% wt of copper, 0.15-7% wt of antimony, 0.012-1.5% wt of bismuth, 0.010-1.1% wt of zinc, at most 3% wt of arsenic, at most 2.8% wt of nickel, at most 0.7% wt of zinc, at most 7.5% wt of iron and at most 0.5% wt of aluminium, from a feedstock selected in terms of its levels of Sn, Cu, Sb, Bi, Zn, As, Ni and Pb, the process comprising at least the steps of obtaining in a furnace a liquid bath of metal and slag, introducing a reducing agent and optionally also energy, separating the crude solder from the slag and removing liquid from the furnace. The crude solder may readily be further prepared to become suitable as feedstock for vacuum distillation.

Processes for forming an electric heater comprise providing a heater element and a power supply, applying a layer of a diffusion solder paste onto the heater element and/or the power supply and drying the applied diffusion solder paste, arranging the heater element and the power supply such that the heater element and the power supply contact each other via the dried diffusion solder paste, and diffusion soldering the arrangement to form a connection between the heater element and the power supply. The diffusion solder paste comprises or consists of 10-30 wt.-% of at least one type of particles selected from the group consisting of copper particles, copper-rich copper/zinc alloy particles, and copper-rich copper/tin alloy particles, 60-80 wt.-% of at least one type of particles selected from tin particles, tin-rich tin/copper alloy particles, tin-rich tin/silver alloy particles, and tin-rich tin/copper/silver alloy particles, and 3-30 wt.-% of a solder flux.

A flux according to the present invention contains a rosin methyl ester in which the flux is a solid or solid-like flux at 25° C., and is used for an inside of a flux-cored solder or an exterior of a flux-coated solder.