Indium-tin-silver alloys suitable for use as a lead free solder are described herein. The alloys may comprise primarily indium or comprise primarily tin. The alloys may further include copper, nickel, and iron or copper, antimony, and zinc. The composition can be used to solder an electrical connector to an electrical contact surface on a glass component. Methods of forming the alloys are also described herein.

A solder composition for use in solder joints of printed circuit boards (PCBs), including a compound layer comprising an alloy of bismuth and tin; and a graphene coating positioned on the compound layer.

Provided is a solder transfer sheet which is capable of increasing the amount of solder to be transferred without the occurrence of bridging. A solder transfer sheet 1A includes a base material 5, an adhesive layer 4 formed on the surface of the base material 5, a solder powder-containing adhesive layer 3 formed on the surface of the adhesive layer 4, and a solder powder layer 2 formed on the surface of the solder powder-containing adhesive layer 3. In the solder powder layer 2, particles of solder powder 20 are arranged in a one-layer sheet form. In the solder powder-containing adhesive layer 3, solder powder 30 and an adhesive component 31 are mixed so as to have such a thickness that two or more layers of the solder powder 30 are stacked.

There is provided a connection structure of a circuit member including: a first circuit member having a first main surface provided with a first electrode; a second circuit member having a second main surface provided with a second electrode; and a joining portion which is interposed between the first main surface and the second main surface, in which the joining portion has a solder portion which electrically connects the first electrode and the second electrode to each other, in which the solder portion contains a bismuth-indium alloy, and in which an amount of bismuth contained in the bismuth-indium alloy exceeds 20% by mass and is equal to or less than 80% by mass.

A flexible printed circuit and a manufacturing method thereof, an electronic device module and an electronic device are provided. The flexible printed circuit includes a main sub-circuit board and a bridge sub-circuit board; the main sub-circuit board includes a first substrate, and a first bridge end, a second bridge end, a first wiring portion, and a second wiring portion on the first substrate, the first wiring portion and the second wiring portion are spaced apart from each other and are electrically connected to the first bridge end and the second bridge end, respectively; the bridge sub-circuit board includes a second substrate, and a third bridge end, a fourth bridge end, and a third wiring portion for a first functional wiring line on the second substrate, the third bridge end and the fourth bridge end are electrically connected by the third wiring portion, the first substrate and the second substrate are not in direct contact, and the bridge sub-circuit board is configured to be mounted on the main sub-circuit board by electrically connecting the third bridge end and the fourth bridge end to the first bridge end and the second bridge end, respectively. The wiring layout of the flexible printed circuit is simple and is easy to be manufactured.

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.

A solder alloy contains 0.5 mass % or more and 1.25 mass % or less of Sb, In which satisfies 5.5≦[In]≦5.50+1.06[Sb] in a case of 0.5≦[Sb]≦1.0; and 5.5≦[In]≦6.35+0.212[Sb] in a case of 1.0<[Sb]≦1.25 (in the expression, [Sb] indicates the Sb content percentage (mass %) and [In] indicates the In content percentage (mass %)), 0.5 mass % or more and 1.2 mass % or less of Cu, 0.1 mass % or more and 3.0 mass % or less of Bi, and 1.0 mass % or more and 4.0 mass % or less of Ag. The remainder is formed from Sn.

A lead-free solder ball is provided which suppresses interfacial peeling in a bonding interface of a solder ball, fusion defects which develop between the solder ball and solder paste, and which can be used both with Ni electrodes plated with Au or the like and Cu electrodes having a water-soluble preflux applied atop Cu. The lead-free solder ball for electrodes of BGAs or CSPs consists of 1.6-2.9 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. It has excellent resistance to thermal fatigue and to drop impacts regardless of the type of electrodes of a printed circuit board to which it is bonded, which are Cu electrodes or Ni electrodes having Au plating or Au/Pd plating as surface treatment. The composition may include at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

A stretchable mounting board that includes: a stretchable substrate; a mounting electrode portion on a main surface side of the stretchable substrate and containing a conductive filler and a resin; a solder portion connected to the mounting electrode portion; and an electronic component electrically connected to the mounting electrode portion with the solder portion interposed therebetween. The mounting electrode portion has a first main surface on a stretchable substrate side thereof, a second main surface on a solder portion side thereof, a first region including the first main surface, and a second region including the second main surface, and wherein, in a cross-section along a thickness direction of the mounting electrode portion passing through the first region and the second region, a sectional area of the conductive filler in the second region is larger than a sectional area of the conductive filler in the first region.

A solder alloy that contains 0.005 mass % or more and 0.1 mass % or less of Mn, 0.001 mass % or more and 0.1 mass % or less of Ge, and a balance of Sn. A plurality of Ge oxides is distributed on an outermost surface side of an oxide film including Sn oxide, Mn oxide and Ge oxide by adding 0.005 mass % or more and 0.1 mass % or less of Mn, 0.001 mass % or more and 0.1 mass % or less of Ge to the solder alloy having a principal ingredient of Sn, so that it is possible to obtain the discolor-inhibiting effect even under the high-temperature and high-humidity environment.