Patent ID: 8188605

Claim:
A components joining method for electrically connecting a first terminal and a second terminal to each other, wherein the first terminal and the second terminal are provided on a first part and a second part, respectively, and the surfaces of at least one of the first terminal and the second terminal are covered by natural oxide films, and bonding the first part and the second part to each other, comprising the steps of: interposing a solder paste containing solder particles consisting mainly of tin (Sn) in a thermosetting resin between the first part and the second part, wherein the solder particles are covered with oxide films; and electrically connecting the first terminal and the second terminal by the solder particles by pressing the first terminal and the second terminal against each other while heating the first part and/or the second part to form solder portions between the first terminal and the second terminal and bonding the first part and the second part to each other by curing the thermosetting resin, wherein the solder paste contains a latent curing agent for curing the thermosetting resin, and further contains an activator which removes the natural oxide films of the terminal surfaces and the oxide films of the solder particles, wherein the activator is contained in the solder paste in an amount of 1 to 5 weight percent for a portion of the solder paste excluding the solder particles, wherein the amount of the activator is set so that in the electrically connecting step the natural oxide film of the surfaces and the oxide films of the solder particles are partially but not completely removed and the solder particles that do not contribute the formation of the solder portions are covered by the remaining oxide films that are not removed by the activator and in the bonding step the thermosetting resin is cured while the surfaces are partially covered by the remaining natural oxide film and the solder particles are partially covered by the remaining oxide films.