In a lead-free solder bump, diffusion of Cu from intermetallic compound layers, which are respectively formed at joining interfaces with Cu electrodes is suppressed, so that the in metallic compound layers are not likely to disappear. Correspondingly, with the use of the intermetallic compound layers, Cu is not likely to diffuse from the Cu electrodes into the lead-free solder bump. Even when an electric current flows continuously between a first electronic member and a second electronic member through the lead-free solder bump, the occurrences of the electromigration phemenon and the thermomigration phenomenon are suppressed. Thus, the present invention provides a lead-free solder bump joining structure capable of suppressing the disconnection failure caused by the synergistic effect of the electromigration phenomenon and the thermomigration phenomenon.

Provided is a solder alloy, a solder paste, a solder preform, and a solder joint which suppress chip cracking during cooling, improve the heat dissipation characteristics of the solder joint, and exhibit high joint strength at high temperatures.

The solder alloy has an alloy composition of, by mass: Sb: 9.0 to 33.0%; Ag: more than 4.0% and less than 11.0%; and Cu: more than 2.0% and less than 6.0%, with the balance of Sn.

Moreover, the solder paste, the solder preform, and the solder joint all contain said solder alloy.

Provided is a solder alloy, a solder paste, a solder preform, and a solder joint which suppress chip cracking during cooling, improve the heat dissipation characteristics of the solder joint, and exhibit high joint strength at high temperatures.

The solder alloy has an alloy composition of, by mass: Sb: 9.0 to 33.0%; Ag: more than 4.0% and less than 11.0%; and Cu: more than 2.0% and less than 6.0%, with the balance of Sn.

Moreover, the solder paste, the solder preform, and the solder joint all contain said solder alloy.

A lead-free solder has a heat resistance temperature which is high and a thermal conductive property which is not changed in a high temperature range. A semiconductor device includes a solder material containing more than 5.0% by mass and 10.0% by mass or less of Sb and 2.0 to 4.0% by mass of Ag, an element selected from the group consisting of: more than 0 and 1.0% by mass or less of Si, more than 0 and 0.1% by mass or less of V, 0.001 to 0.1% by mass of Ge, 0.001 to 0.1% by mass of P, and more than 0 and 1.2% by mass or less of Cu, and the remainder consisting of Sn and inevitable impurities. A bonding layer including the solder material, is formed between a semiconductor element and a substrate electrode or a lead frame.

A lead-free solder has a heat resistance temperature which is high and a thermal conductive property which is not changed in a high temperature range. A semiconductor device includes a solder material containing more than 5.0% by mass and 10.0% by mass or less of Sb and 2.0 to 4.0% by mass of Ag, an element selected from the group consisting of: more than 0 and 1.0% by mass or less of Si, more than 0 and 0.1% by mass or less of V, 0.001 to 0.1% by mass of Ge, 0.001 to 0.1% by mass of P, and more than 0 and 1.2% by mass or less of Cu, and the remainder consisting of Sn and inevitable impurities. A bonding layer including the solder material, is formed between a semiconductor element and a substrate electrode or a lead frame.

A flux comprising an organic acid; a solvent; and polyoxyethylene behenyl alcohol having an average number of moles of ethylene oxide added of 7 to 40 mol.

A flux used for soldering with a tin-silver-copper alloy comprises an imidazole compound and/or an imidazoline compound; a dicarboxylic acid having 3 or more and 36 or less carbons; and a quaternary ammonium iodine salt. Relative to the total amount of the flux, the dicarboxylic acid content is 6 mass % or more and 25 mass % or less, and the iodine content is 200 ppm or more and 3600 ppm or less.

Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.

Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.

The present invention provides a solder material containing Sn or a Sn-containing alloy and 40 to 320 ppm by mass of A, the solder material including an As-enriched layer.