The object of the present invention is to provide a flux composition and a solder paste composition in which scattering of flux is suppressed. A flux composition comprising an anti-scattering agent represented by formula (1) below, ##STR00001##
wherein Z is optionally substituted alkylene, R.sup.1 and R.sup.2 are each independently optionally substituted alkyl, optionally substituted aralkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted cycloalkyl, or optionally substituted heterocycloalkyl, R.sup.3 and R.sup.4 are each independently optionally substituted alkyl.

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.

A metal particle for joint material includes an intermetallic compound crystal that contains Sn, Cu, Ni and Ge, in a basal phase that contains Sn and an Sn—Cu alloy, the metal particle having a chemical composition represented by 0.7 to 15% by mass of Cu, 0.1 to 5% by mass of Ni, 0.001 to 0.1% by mass of Ge and the balance of Sn, the basal phase having a chemical composition represented by 95 to 99.9% by mass of Sn, 5% by mass or less of Cu and 0.1% by mass or less of an inevitable impurity, the intermetallic compound crystal residing in the basal phase so as to be included therein, the metal particle having a particle size of 1 μm to 50 μm, the metal particle containing an orthorhombic crystal structure, and at least parts of the basal phase and the intermetallic compound crystal forming an endotaxial joint.

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.

A method is disclosed for electrically bonding a first semiconductor component to a second semiconductor component, both components including arrays of contact areas. In one aspect, prior to bonding, layers of an intermetallic compound are formed on the contact areas of the second component. The roughness of the intermetallic layers is such that the intermetallic layers include cavities suitable for insertion of a solder material in the cavities, under the application of a bonding pressure, when the solder is at a temperature below its melting temperature. The components are aligned and bonded, while the solder material is applied between the two. Bonding takes place at a temperature below the melting temperature of the solder. The bond can be established only by the insertion of the solder into the cavities of the intermetallic layers, and without the formation of a second intermetallic layer.

The invention relates to a soldering material comprising an alloy that in addition to Sn (tin) as the major constituent, comprises 10 wt. % or less Ag (silver), 10 wt. % or less Bi (bismuth), 10 wt. % or less Sb (antimony) and 3 wt. % or less Cu (copper). Furthermore, the invention relates to a soldering material comprising a plurality of soldering components with such alloy compositions and contents in the soldering material that on fusing the soldering components an alloy is formed that comprises Sn, Ag, Bi, Sb and Cu in the abovementioned alloy contents.

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.

Some implementations of the disclosure relate to a lead-free solder paste with mixed solder powders that is particularly suitable for high temperature soldering applications involving multiple board-level reflow operations. In one implementation, the solder paste consists of 10 wt % to 90 wt % of a first solder alloy powder, the first solder alloy powder consisting of an SnSbCuAg solder alloy that has a wt % ratio of Sn:Sb of 0.75 to 1.1; 10 wt % to 90 wt % of a second solder alloy powder, the second solder alloy powder consisting of an Sn solder alloy including at least 80 wt % of Sn; and a remainder of flux.

An electrical connector includes a first layer formed of a copper based material and a second layer formed of an iron-nickel alloy. The second layer has a thickness of 8% to 30% of the thickness of the electrical connector. The electrical connector also includes a third layer which is formed of a solder alloy that consists essentially of 17% to 28% indium by weight, 12% to 20% zinc by weight, 1% to 6% silver by weight, 1% to 3% copper by weight, and a remaining weight of the solder alloy that is tin.

A solder joint which is used in power devices and the like and which can withstand a high current density without developing electromigration is formed of a Sn—Ag—Bi—In based alloy. The solder joint is formed of a solder alloy consisting essentially of 2-4 mass % of Ag, 2-4 mass % of Bi, 2-5 mass % of In, and a remainder of Sn. The solder alloy may further contain at least one of Ni, Co, and Fe.