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 component mounting method includes an application step of applying a specific solder paste including Sn and a metal other than Sn to a board; a disposition step of positioning and disposing an upper surface reference type component having a positioning reference on an upper surface with respect to one or more reference points on the board; and a reflow step of reflow-soldering the component by heating the board, in which in the specific solder paste, at least a part of the Sn is melted, and molten Sn and the metal other than Sn form an intermetallic compound in the reflow step, thereby fixing the upper surface reference type component to the board.

A magnetic-field melting solder that melts by the action of an AC magnetic field is provided. The magnetic-field melting solder includes solder material; and magnetic material composing of ferrite or Ni, a proportion of the magnetic material to the entire magnetic-field melting solder being 0.005% to 5% by weight. A joining method using the magnetic-field melting solder includes providing the magnetic-field melting solder between an electrode on a substrate and an electrode of an electronic component, and joining together the electrode on the substrate and the electrode of the electronic component by generating an AC magnetic field around the substrate and thereby melting the magnetic-field melting solder.

A solder paste includes a first solder alloy powder in an amount ranging from 30% to 95% by weight. The first solder alloy powder includes a first solder alloy with a solidus temperature of 200° C. to 260° C. The first solder alloy includes an Sn—Cu alloy or an Sn—Cu—Ag alloy. The solder paste further includes a second solder alloy powder in an amount ranging from 5% to 70% by weight, and a solder flux. The second solder alloy powder includes a second solder alloy with a solidus temperature below 250° C. The solder paste has a variable melting point. In multiple reflow soldering, a remelting of the solder paste is inhibited under different temperature conditions so that no functional failure occurs during assembly and/or packaging of PCBs or electronic devices due to melting of solder.

Provided are a Sn—Bi—In-based low melting-point joining member used in a Pb-free electroconductive joining method in mounting a semiconductor component, and is usable for low-temperature joining, and a manufacturing method therefor.

A Sn—Bi—In-based low melting-point joining member, including a Sn—Bi—In alloy that has a composition within a range represented by a quadrangle in a Sn—Bi—In ternary phase diagram, a first quadrangle having four vertices including: Point 1 (1, 69, 30), Point 2 (26, 52, 22), Point 3 (40, 10, 50), and Point 4 (1, 25, 74), where Point (x, y, z) is defined as a point of x mass % Sn, y mass % Bi and z mass % In, and that also has a melting point of 60 to 110° C. As well as a method for producing a Sn—Bi—In-based low melting-point joining member, including a plating step of forming a plated laminate on an object to be plated, the plated laminate including a laminated plating layer obtained by performing Sn plating, Bi plating, and In plating respectively such that the laminated plating layer has a composition within the range represented by the first quadrangle.

Some implementations of the disclosure describe a solder paste consisting essentially of: 10 wt % to 90 wt % of a first solder alloy powder, the first solder alloy powder consisting of a Sn—Sb alloy, a Sn—Ag—Cu—Sb alloy, a Sn—Ag—Cu—Sb—In alloy, a Sn—Ag—Cu—Sb—Bi alloy, or Sn—Ag—Cu—Sb—Bi—In alloy; 10 wt % to 90 wt % of a second solder alloy powder, the second solder alloy powder consisting of an Sn—Ag—Cu alloy or Sn—Ag—Cu—Bi alloy, and the second solder alloy powder having a lower solidus temperature than the first solder alloy powder; and flux.

There is provided a bonding material which forms a bonding portion between two objects, which material contains (1) first metal particles comprising a first metal and having a median particle diameter in the range of 20 nm to 1 μm, and (2) second metal particles comprising, as a second metal, at least one alloy of Sn and at least one selected from Bi, In and Zn and having a melting point of not higher than 200° C.