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.

Ni—Mn—Si based braze filler alloys or metals which may be nickel-rich, manganese-rich, or silicon-rich braze filler alloys, have unexpectedly narrow melting temperature ranges, low solidus and low liquidus temperatures, as determined by Differential Scanning calorimetry (DSC), while exhibiting good wetting, and spreading, without deleterious significant boride formation into the base metal, and can be brazed at lower temperatures. The nickel rich alloys contain 58 wt % to 70 wt % nickel, the manganese-rich alloys contain 55 wt % to 62 wt % manganese, and the silicon-rich alloys contain 25 wt % to 29 wt % silicon. Copper with or without boron to partly replace nickel may be employed without any substantial increase of the melting point, or to reduce the melting point. The braze filler alloys have sufficient brazability to withstand high temperature conditions for thin-walled aeronautical and other heat exchangers.

Some implementations of the disclosure are directed to low melting temperature (e.g., liquidus temperature below 210° C.) SnIn solder alloys. A SnIn solder alloy may consist of: 8 to 20 wt % In; greater than 0 wt % to 4 wt % Ag; optionally, one or more of greater than 0 wt % to 5 wt % Sb, greater than 0 wt % to 3 wt % Cu, greater than 0 wt % to 2.5 wt % Zn, greater than 0 wt % to 1.5 wt % Ni, greater than 0 wt % to 1.5 wt % Co, greater than 0 wt % to 1.5 wt % Ge, greater than 0 wt % to 1.5 wt % P, and greater than 0 wt % to 1.5 wt % Mn; and a remainder of Sn.

A microelectronic device has bump bond structures on input/output (I/O) pads. The bump bond structures include copper-containing pillars, a barrier layer including cobalt and zinc on the copper-containing pillars, and tin-containing solder on the barrier layer. The barrier layer includes 0.1 weight percent to 50 weight percent cobalt and an amount of zinc equivalent to a layer of pure zinc 0.05 microns to 0.5 microns thick. A lead frame has a copper-containing member with a similar barrier layer in an area for a solder joint. Methods of forming the microelectronic device are disclosed.

A solder alloy comprises Ag: 3.1 to 4.0% by mass, Cu: 0.6 to 0.8% by mass, Bi: 1.5 to 5.5% by mass, Sb: 1.0 to 6.0% by mass, Co: 0.001 to 0.030% by mass, Fe: 0.02 to 0.05% by mass, and a balance Sn.

A lead-free solder material is provided. In one example, the solder material may include solder particles including at least 30 wt % nickel, and an activator including or consisting of at least one of a group of activator materials, the group including an organic acid or salt thereof, and an amine or salt thereof.

A brazing material for brazing a brazed plate heat exchanger comprising a number of heat exchanger plates being provided with a pressed pattern of ridges and grooves adapted to provide contact points between neighbouring heat exchanger plates, such that the heat exchanger plates are kept on a distance from one another and such that interplate flow channels for media to exchange heat are formed between the heat exchanger plates comprises a brazing alloy comprising at least one melting point depressing element and metals resembling the composition of the heat exchanger plates. The brazing material comprises a mixture between grains of a melting brazing material having solidus and liquidus temperatures lower than a brazing temperature and a non-melting brazing material having solidus and liquidus temperatures above the brazing temperature. The ratio between the melting and non-melting brazing materials is such that an alloy formed by the melting and non-melting brazing materials has a solidus temperature lower than the brazing temperature and a liquidus temperature higher than the brazing temperature.

If a flux contains an amount of thixotropic agent necessary for obtaining the effect of suppressing a heating sagging, the amount of flux residue increases, and, if applied for uses that do not involve washing, a large amount of flux residue derived from the thixotropic agent remains around the soldered portions, thereby affecting chemical and electrical reliability; and that washing performance is poor in uses involving washing of the flux residue. Accordingly, this soldering flux contains nanofibers of one or more kinds from among polysaccharides, modified polysaccharides, and incompletely modified polysaccharides being modified from polysaccharides into modified polysaccharides, by an amount of 50 wt ppm or more and 3000 wt ppm or less with respect to a total amount of flux.

Provided are a solder alloy which has excellent temperature cycle characteristics and in which yellowish discoloration is suppressed, excellent wettability is maintained, and an increase in viscosity of a solder paste over time can be suppressed, and a solder paste, a solder ball, and a solder joint in which the solder alloy is used. The solder alloy consists of, by mass %, 1.0% to 5.0% of Ag, 0.5% to 3.0% of Cu, 0.5% to 7.0% of Sb, 0.0040% to 0.025% of As, and a balance of Sn.

A flux containing an organic acid, an acrylic resin, a rosin, a thixotropic agent, and a solvent, but not containing water is adopted. In this flux, the organic acid includes 1,2,3-propanetricarboxylic acid, and the content of the 1,2,3-propanetricarboxylic acid is 0.1% by mass or more and 15% by mass or less with respect to the total amount of the entire flux. According to this flux, the wettability of solder can be enhanced, temperature cycle reliability is excellent, and scattering due to heating during reflow can be suppressed.