Provided is a lead-free solder alloy that has excellent tensile strength and ductility, does not deform after heat cycles, and does not crack. The In and Bi content are optimized and the Sb and Ni content are adjusted. As a result, this solder alloy has an alloy composition including, by mass, 1.0 to 7.0% of In, 1.5 to 5.5% of Bi, 1.0 to 4.0% of Ag, 0.01 to 0.2% of Ni, and 0.01 to 0.15% of Sb, with the remainder made up by Sn.

Provided is a lead-free solder alloy that has excellent tensile strength and ductility, does not deform after heat cycles, and does not crack. The In and Bi content are optimized and the Sb and Ni content are adjusted. As a result, this solder alloy has an alloy composition including, by mass, 1.0 to 7.0% of In, 1.5 to 5.5% of Bi, 1.0 to 4.0% of Ag, 0.01 to 0.2% of Ni, and 0.01 to 0.15% of Sb, with the remainder made up by Sn.

A semiconductor device includes a semiconductor chip made of a SiC substrate and having main electrodes on one surface and a rear surface, first and second heat sinks, respectively, disposed adjacent to the one surface and the rear surface, a terminal member interposed between the second heat sink and the semiconductor chip, and a plurality of bonding members disposed between the main electrodes, the first and second heat sinks, and the terminal member. The terminal member includes plural types of metal layers symmetrically layered in the plate thickness direction. The terminal member as a whole has a coefficient of linear expansion at least in a direction orthogonal to the plate thickness direction in a range larger than that of the semiconductor chip and smaller than that of the second heat sink.

Solder paste consisting of 85 to 92% by weight of a tin-based solder and 8 to 15% by weight of a flux, wherein the flux comprises i) 30 to 50% by weight, based on its total weight, of a combination of at least two optionally modified natural resins, ii) 5 to 20% by weight, based on its total weight, of at least one low-molecular carboxylic acid; and iii) 0.4 to 10% by weight, based on its total weight, of at least one amine, and wherein the combination of the optionally modified natural resins has an integral molecular weight distribution of 45 to 70% by area in the molecular weight range of 150 to 550 and of 30 to 55% by area in the molecular weight range of >550 to 10,000 in the combined GPC.

A lead-free soldering foil, for connecting metal and/or metal-coated components. allows the setting of a defined connecting-zone geometry and, with pores and/or voids being formed only to a minimal extent, achieves a high-temperature-resistant soldered connection that ensures great reliability even in staged soldering processes and increases the thermal conductivity of the connecting zone. The lead-free soldering foil is constructed so that, in a soft-solder matrix, two or more composite wires are each individually sandwiched by roll cladding between two soft-solder strips, parallel to one another and parallel to the edges of the strips. These composite wires include a core, which contains a higher-melting, stronger metal/metal alloy in comparison with the soft-solder matrix and around which a shell of another metal/metal alloy is arranged, and, after the roll-cladding operation, there is still 5 pm to 15 pm of soft-solder material arranged above and below at least one of the cores.

In a layered bonding material 10, a coefficient of linear expansion of a base material 11 is 5.5 to 15.5 ppm/K and a first surface and a second surface of the base material 11 are coated with pieces of lead-free solder 12a and 12b.

A lead-free soldering foil, for connecting metal and/or metal-coated components. allows the setting of a defined connecting-zone geometry and, with pores and/or voids being formed only to a minimal extent, achieves a high-temperature-resistant soldered connection that ensures great reliability even in staged soldering processes and increases the thermal conductivity of the connecting zone. The lead-free soldering foil is constructed so that, in a soft-solder matrix, two or more composite wires are each individually sandwiched by roll cladding between two soft-solder strips, parallel to one another and parallel to the edges of the strips. These composite wires include a core, which contains a higher-melting, stronger metal/metal alloy in comparison with the soft-solder matrix and around which a shell of another metal/metal alloy is arranged, and, after the roll-cladding operation, there is still 5 pm to 15 pm of soft-solder material arranged above and below at least one of the cores.

A method for step-soldering includes applying a first solder alloy having a melting point in a temperature range from 160 to 210° C. to a jointed portion of a first electronic component and a substrate, and heating them in the temperature range from 160 to 210° C., and applying a second solder alloy having the melting point in a temperature range lower than 160° C. to a joint portion of a second electronic component and the substrate, and heating them in the temperature range lower than 160° C. The first solder alloy consists 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 field device for processing and automation technology includes a first and a second component that can each be mechanically connected at a joining surface by means of a joining point. Two metal surface layers are each applied at least to the joining surface of the first component and the joining surface of the second component. The metal of the surface layers is different from the metal of the first and/or the metal of the second component. A joining material is applied between the respective joining surfaces of the two components, wherein the joining material includes particles at least partially consisting of a metal that corresponds with the metal of the surface layers The joining of the two components occurs at a joining temperature below 300° C.

A flux according to the present invention includes a phosphine oxide. It is thereby possible to provide a flux capable of improving solder wettability, a resin flux cored solder including the flux, and a solder paste including the flux.