Provided is a flux which can remove metal oxides to improve solder wettability and can fix the object to be soldered with flux residue. The flux contains thermosetting resin, and long-chain dibasic acid mixture including one or more species of first long-chain dibasic acid having an alkyl group in a side chain, the first long-chain dibasic acid being added as a hardening agent for hardening the thermosetting resin and an activator, and second long-chain dibasic acid having an alkyl group and an alkoxycarbonyl group in a side chain and having carbon number of 8 or more in a main chain between the carboxyl groups at opposite terminals. It is preferable that content of the thermosetting resin is 30% through 70% and content of the long-chain dibasic acid mixture is 20% through 60%.

A braided solder wire rope includes a first alloy including BiAg, BiCu, BiAgCu, or BiSb; and the second alloy including Sn, In SnAg, SnCu, SnAgCu, SnZn, BiSn, SnIn, SnSb or BiIn, such that the second alloy controls an interface reaction chemistry with various metallization surface finish materials without interfering with a high temperature performance of the first alloy. The first alloy may have a solidus temperature around 258 C. and at least the first alloy of the first wire and the second alloy of the second wire may be braided together.

A method of assembling components, such as electronic components, onto a substrate, such as an electronic substrate, includes applying solder paste to an electronic substrate to form a solder paste deposit, placing a low temperature preform in the solder paste deposit, processing the electronic substrate at a reflow temperature of the solder paste to create a low temperature solder joint, and processing the low temperature solder joint at a reflow temperature that is lower than the reflow temperature of the solder paste. Other methods of assembling components and solder joint compositions are further disclosed.

Solder particles include composite solder particles at a percentage of 5% by number or less in a total of the solder particles, the composite solder particles including multiple adhered solder particles. A solder particle production method includes an impact force application step of applying an impact force to solder particles so that a percentage of composite solder particles becomes 5% 10 by number or less in a total of the solder particles, the composite solder particles including multiple adhered solder particles.

A solder alloy includes 35 mass % or more and 65 mass % or less of Bi, 0.1 mass % or more and 0.65 mass % or less of Sb, 0.05 mass % or more and 2 mass % or less of Ag, and a balance including Sn and an inevitable impurity.

A material includes a plurality of supercooled micro-capsules each including a metallic core in a liquid state at a temperature below a solidification temperature of the metallic core and further includes a metallic shell surrounding each respective metallic core. A plurality of alloyed metallic particles and flux are mixed with the plurality of supercooled micro-capsules to form a solder paste. Upon heating the solder paste, the plurality of alloyed particles melt. As the metallic shells destabilize, the liquid metallic cores interdiffuse with the melted alloyed particles forming a new alloy that has a higher melting temperature than the melting temperature of the alloyed metallic particles.

An electronic apparatus includes a first electronic part with a first terminal, a second electronic part with a second terminal opposite the first terminal, and a joining portion which joins the first terminal and the second terminal. The joining portion contains a pole-like compound extending in a direction in which the first terminal and the second terminal are opposite to each other. The joining portion contains the pole-like compound, so the strength of the joining portion is improved. When the first terminal and the second terminal are joined, the temperature of one of the first electronic part and the second electronic part is made higher than that of the other. A joining material is cooled and solidified in this state. By doing so, the pole-like compound is formed.

A lead-free solder wire includes a core wire with a first alloy and a shell coating layer with a second alloy. The first alloy may be composed of BiAg, BiCu, BiAgCu, or BiSb; and the second alloy may be composed of Sn, In SnAg, SnCu, SnAgCu, SnZn, BiSn, SnIn, SnSb or BiIn, such that the shell coating layer is applied to a surface of the core wire. In another implementation, the lead free solder wire may include a first wire with a first alloy and a second wire with a second alloy. The first alloy may be composed of BiAg, BiCu, BiAgCu, or BiSb; and the second alloy may be composed of Sn, SnAg, SnCu, SnAgCu, SnZn, BiSn, SnIn, SnSb or BiIn, such that the first alloy of the first wire and the second alloy of the second wire are braided together.

The invention provides an alloy, preferably a lead-free solder alloy, comprising: from 35 to 59% wt Bi; from 0 to .0 wt % Ag; from 0 to 1.0% wt Au; from 0 to 1.0% wt Cr; from 0 to 2.0% wt In; from 0 to 1.0% wt P; from 0 to 1.0% wt Sb; from 0 to 1.0% wt Sc; from 0 to 1.0% wt Y; from 0 to 1.0% wt Zn; from 0 to 1.0% wt rare earth elements; one or more of: 10 from greater than 0 to 1.0% wt Al; from 0.01 to 1.0% wt Ce; from greater than 0 to 1.0% wt Co; from greater than 0 to .0% wt Cu; from 0.001 to 1.0% wt Ge; from greater than 0 to .0% wt Mg; from greater than 0 to 1.0% wt Mn; from 0.01 to 1.0% wt Ni; and from greater than 0 to 1.0% wt Ti, and the 1 balance Sn, together with any unavoidable impurities.

An electronic apparatus includes a first electronic part with a first terminal, a second electronic part with a second terminal opposite the first terminal, and a joining portion which joins the first terminal and the second terminal. The joining portion contains a pole-like compound extending in a direction in which the first terminal and the second terminal are opposite to each other. The joining portion contains the pole-like compound, so the strength of the joining portion is improved. When the first terminal and the second terminal are joined, the temperature of one of the first electronic part and the second electronic part is made higher than that of the other. A joining material is cooled and solidified in this state. By doing so, the pole-like compound is formed.