Solder pastes comprise a high temperature solder powder, a low temperature solder powder and flux. The melting temperature of the low temperature solder powder is lower than that of the high temperature solder powder. The high temperature solder powder and the low temperature solder powder are both capable of wetting upon heating.

A solder product 20 includes: a lead-free solder part 21 containing tin as a main component and a metal element other than lead as a secondary component; and a carboxylic acid having 10 to 20 carbons, the carboxylic acid being mainly distributed over the surface of the solder product 20 to form a surface layer 22. The carboxylic acid is preferably a fatty acid having 12 to 16 carbons, and more preferably a palmitic acid.

A resin flux solder paste includes a solder powder, and a flux, in which the flux contains at least an epoxy resin, a curing agent, a curing accelerator, and an activator, the epoxy resin contains 10% to 90% by weight of one or more of a biphenyl aralkyl type epoxy resin, a naphthalene type epoxy resin, and a dicyclopentadiene type epoxy resin, having an epoxy equivalent of 200 to 400, with respect to a total amount of the epoxy resin, and the curing agent contains 30% to 95% by weight of a biphenyl aralkyl phenol resin having a hydroxyl group equivalent of 150 to 350 with respect to a total amount of the curing agent, and 5% to 70% by weight of a phenol novolac resin having an allyl group having a hydroxyl group equivalent of 100 to 200 with respect to the total amount of the curing agent.

The disclosure relates to a printed circuit board having at least two current-conducting layer plies, wherein the current-conducting layer plies extend in an axial direction of the printed circuit board and are arranged in succession in a thickness direction of the printed circuit board. A component fastened by THT is arranged on one side of the printed circuit board. At least one connecting element extends through the printed circuit board through a passage opening in the thickness direction. The current-conducting layer ply is adjacent to the component fastened by THT reaches as far as the connecting element and the current-conducting layer ply that is remote from the component fastened by THT is at a distance from the connecting element.

A disk having at least one electric connecting element is described. The disk has a substrate, and electrically conductive structure on a region of the substrate, a connecting element containing at least chromium-containing steel, and a layer of a soldering compound that electrically connects the connecting element to sub-regions of the electrically conductive structure.

A solder alloy has an alloy composition consisting of, in mass %, Ag: from 3.2 to 3.8%, Cu: from 0.6 to 0.8%, Ni: from 0.01 to 0.2%, Sb: from 2 to 5.5%, Bi: from 1.5 to 5.5%, Co: from 0.001 to 0.1%, Ge: from 0.001 to 0.1%, and optionally at least one of Mg, Ti, Cr, Mn, Fe, Ga, Zr, Nb, Pd, Pt, Au, La and Ce: 0.1% or less in total, with the balance being Sn. The alloy composition satisfies the following relationship (1): 2.93≤{(Ge/Sn)+(Bi/Ge)}×(Bi/Sn) (1). In the relationship (1), each of Sn, Ge, and Bi represents the content (mass %) in the alloy composition.

The present disclosure is directed to an electronic component mounting structure including: a circuit board provided on a surface thereof with a first electrode containing Cu as a main component; and an electronic component mounted on the circuit board, the electronic component including a second electrode on a surface thereof; wherein the second electrode includes a first plating containing Ni as a main component and a second plating containing Sn as a main component formed on a surface of the first plating, and an intermediate bonding layer is provided between the first plating and the first electrode, and the intermediate bonding layer includes a first region containing an alloy of Cu and Sn as a main component and a second region containing Sn as a main component.

A tin or tin alloy plating solution includes: (A) a soluble salt containing at least a stannous salt; (B) an acid selected from an organic acid and an inorganic acid or a salt thereof; (C) a phenyl-based surfactant formed of polyoxyethylene bisphenol ether represented by the General Formula (1); and (D) a leveling agent, ##STR00001##
here, in the Formula (1), X is C.sub.aH.sub.2a (a is 1 or 3) and m is 2 to 12.

A lead-free, antimony-free tin solder which is reliable at high temperatures and comprises from 3.5 to 4.5 wt.% of silver, 2.5 to 4 wt.% of bismuth, 0.3 to 0.8 wt.% of copper, 0.03 to 1 wt.% nickel, 0.005 to 1 wt.% germanium, and a balance of tin, together with any unavoidable impurities.

A passive circuit element is disclosed. The passive circuit element includes an array of conductive pads arranged on a substrate such that a gap is formed between each of the conductive pads. The passive circuit element further includes a first wire electrically connected to a first conductive pad of the array of conductive pads such that the first wire passes through a first gap formed between a second conductive pad and a third conductive pad. The passive circuit element further includes a second wire electrically connected to a fourth conductive pad of the array of conductive pads such that the second wire passes through the first gap. At least one of the second and third conductive pads has a substantially planar side facing toward the first gap.