Abstract: Provided is a joint structure. The joint structure includes a first structure, and a second structure joined to the first structure via a joint portion formed of a Au—Sn-based alloy, wherein a thickness of the joint portion is 3 ?m or more and 50 ?m or less.

Abstract: In a lead-free solder bump, diffusion of Cu from intermetallic compound layers, which are respectively formed at joining interfaces with Cu electrodes is suppressed, so that the in metallic compound layers are not likely to disappear. Correspondingly, with the use of the intermetallic compound layers, Cu is not likely to diffuse from the Cu electrodes into the lead-free solder bump. Even when an electric current flows continuously between a first electronic member and a second electronic member through the lead-free solder bump, the occurrences of the electromigration phemenon and the thermomigration phenomenon are suppressed. Thus, the present invention provides a lead-free solder bump joining structure capable of suppressing the disconnection failure caused by the synergistic effect of the electromigration phenomenon and the thermomigration phenomenon.

Abstract: Provided are a solder ball having extremely excellent drop impact resistance and an electronic member comprising the solder ball. The solder ball of the present invention contains Ni in an amount of from 0.04 to 0.2% by mass and the balance is Sn and incidental impurities, and Cu is not more than a detection limit of the ICP analysis. Hence, it is possible to provide the solder ball having extremely excellent drop impact resistance and an electronic member comprising the solder ball.