A solder alloy has an alloy composition consisting of, in mass %, Cu: 0.1% to 2.0%, Ni: 0.01% to 0.4%, P: 0.001% to 0.08%, and Ge: 0.001% to 0.08%, with the balance being Sn. The alloy composition satisfies the following relations (1) to (3): (Cu+5Ni)≤0.945% (relation (1)), (P+Ge)≤0.15% (relation (2)), 2.0≤(Cu+5Ni)/(P+Ge)≤1000 (relation (3)). In the above relations (1) to (3), Cu, Ni, P, and Ge each represents a content (mass %) thereof in the solder alloy.

A solder alloy has an alloy composition consisting of, in mass %, Cu: 0.1% to 2.0%, Ni: 0.01% to 0.4%, P: 0.001% to 0.08%, and Ge: 0.001% to 0.08%, with the balance being Sn. The alloy composition satisfies the following relations (1) to (3): (Cu+5Ni)≤0.945% (relation (1)), (P+Ge)≤0.15% (relation (2)), 2.0≤(Cu+5Ni)/(P+Ge)≤1000 (relation (3)). In the above relations (1) to (3), Cu, Ni, P, and Ge each represents a content (mass %) thereof in the solder alloy.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380° C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380° C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380° C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380° C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

Provided are a solder alloy and a solder joint, which have a narrow ΔT to suppress solder bridges and solder icicles, and a small amount of dross generated in a solder tank, suppress Cu leaching, and have higher strength. The solder alloy has an alloy composition of, by mass %, Cu: more than 2.0% and less than 3.0%; Ni: 0.010% or more and less than 0.30%; and Ge: 0.0010 to 0.20% with the balance being Sn. Preferably, by mass %, Cu is more than 2.5% and less than 3.0%, and the alloy composition satisfies the following relations (1) and (2): ≤2.400≤Cu+Ni+Ge≤3.190 (1), and 0.33≤Ge/Ni≤1.04 (2). Cu, Ni, and Ge in the relations (1) and (2) each represent the contents (mass %) in the alloy composition.

Provided are a solder alloy and a solder joint, which have a narrow ΔT to suppress solder bridges and solder icicles, and a small amount of dross generated in a solder tank, suppress Cu leaching, and have higher strength. The solder alloy has an alloy composition of, by mass %, Cu: more than 2.0% and less than 3.0%; Ni: 0.010% or more and less than 0.30%; and Ge: 0.0010 to 0.20% with the balance being Sn. Preferably, by mass %, Cu is more than 2.5% and less than 3.0%, and the alloy composition satisfies the following relations (1) and (2): ≤2.400≤Cu+Ni+Ge≤3.190 (1), and 0.33≤Ge/Ni≤1.04 (2). Cu, Ni, and Ge in the relations (1) and (2) each represent the contents (mass %) in the alloy composition.

A solder paste includes a solder powder and a flux. The flux includes a rosin, an activator, a solvent, and a thixotropic agent containing a polyethylene glycol. A content of the polyethylene glycol is 10 mass % to 20 mass % with respect to a total mass of the flux, a content of the thixotropic agent excluding the polyethylene glycol is 5 mass % or less with respect to the total mass of the flux, and a content of the rosin is more than 15 mass % and 50 mass % or less with respect to the total mass of the flux.

Provided are a solder alloy, a solder ball, and a solder joint which have an excellent pin contact performance and a high bonding strength. The solder alloy has an alloy composition consisting of, by mass %, Ag: 0.8 to 1.5%, Cu: 0.1 to 1.0%, Ni: 0.01 to 0.10%, and P: 0.006% to 0.009%, with the balance being Sn. The alloy composition preferably satisfies the following relations (1) and (2): 2.0≤Ag×Cu×Ni/P≤25, 0.500≤Sn×P≤0.778. Ag, Cu, Ni, P, and Sn in the relations (1) and (2) each represent the contents (mass %) in the alloy composition.