Abstract: A solder paste according to an aspect of the invention includes, within a flux, an activator that has a dibasic acid with a molecular weight of 250 or less, a monobasic acid with a molecular weight of 150 or greater and 300 or less, and a dibasic acid with a molecular weight of 300 or greater and 600 or less; and at least one resin additive selected from the group consisting of high-density polyethylenes and polypropylenes. The solder paste has the resin additive in an amount of 4% by weight or greater and 12% by weight or less when the total amount of the flux is taken as 100% by weight, and has a viscosity of 400 Pa·s or greater at 80° C.

Abstract: A flux for a solder paste according to an aspect of the invention includes an acrylic resin obtained by radically copolymerizing a (meth)acrylate having a C6-C15 alkyl group and a (meth)acrylate other than the above-mentioned (meth)acrylate; and rosins. The weight ratio of the acrylic resin is 0.5 or greater and 1.2 or less when the weight of the rosins is taken as 1, and the flux for a solder paste is fluidized by application of a shear force of 10 Pa or greater and 150 Pa or less.

Abstract: The present invention is a method to manufacture the SnZnNiCu solder powder through liquid quenching atomizing method, and an atomizing temperature is not less than 500° C., in particular, not less than 900° C. The raw material metal used as raw material of the solder powder comprises 3 to 12% by weight of Zn, 1.0 to 15% by weight of the sum of Cu and Ni, and Sn and inevitable impurities for the rest, to the total amount of raw material. Thereby, high joint strength is achieved and the SnZnNiCu solder powder which can improve joint reliability of solder joint part is provided.

Abstract: The present invention provides a solder deposition method that includes the step of forming a dam around an electrode on a substrate, the step of applying a solder precipitating composition to the substrate, and the step of depositing solder on the surface of the electrode while heating the solder precipitating composition applied. This solder deposition method is suitable for forming large bumps at fine pitches. In particular, it is capable of depositing solder in a desired height precisely and easily, and yet preventing occurrence of voids.

Abstract: The present invention is a method to manufacture the SnZnNiCu solder powder through liquid quenching atomizing method, and an atomizing temperature is not less than 500° C., in particular, not less than 900° C. The raw material metal used as raw material of the solder powder comprises 3 to 12% by weight of Zn, 1.0 to 15% by weight of the sum of Cu and Ni, and Sn and inevitable impurities for the rest, to the total amount of raw material. Thereby, high joint strength is achieved and the SnZnNiCu solder powder which can improve joint reliability of solder joint part is provided.

Abstract: The present invention provides a solder deposition method that includes the step of forming a dam around an electrode on a substrate, the step of applying a solder precipitating composition to the substrate, and the step of depositing solder on the surface of the electrode while heating the solder precipitating composition applied. This solder deposition method is suitable for forming large bumps at fine pitches. In particular, it is capable of depositing solder in a desired height precisely and easily, and yet preventing occurrence of voids.

Abstract: The invention provides a solder-precipitating composition containing Sn-Pb alloy powder and an organic acid salt of Pb as essential components, and capable of precipitating solder as a result of substitution between Sn contained in the Sn-Pb alloy powder and Pb contained in the organic acid salt of Pb. Further, the invention provides a mounting method including the steps of supplying a conductor on a board with a solder-precipitating composition which contains Sn-Pb alloy powder and an organic acid salt of Pb as essential components, heating the solder-precipitating composition supplied on the conductor, to precipitate solder on the conductor and pre-coat the conductor with solder, as a result of substitution reaction between Sn in the Sn-Pb alloy powder and Pb ions in the organic acid salt of Pb, mounting a device on the solder pre-coated conductor, and melting the solder layer to securely mount the device on the conductor.

Abstract: A large number of pads, to which component leads are to be soldered, are formed on an insulating substrate so as to constitute a pad array. Colder layers are precoated on the pads. Each of the pads has a component lead mounting portion where a component lead is to be mounted, and a component lead non-mounting portion where no component lead is to be mounted. The component lead non-mounting portion includes a wide part having a width greater than that of the component lead mounting portion.