| abstract |
An electronic device comprising a first circuit element and a second circuit element, which are connected by a bonding-bumps structure, said bonding-bumps structure comprising: bonding-bump (1) of small dimensions comprises a gold pedestal portion (2) formed on a circuit element (10), a nickel barrier layer (3) formed on the pedestal portion (2), and a soldering portion (5) formed on the barrier layer (3). The soldering portion (5) comprises first (6) and second (8) gold layers having an intermediate tin layer (7) sandwiched therebetween. The relative masses of gold and tin in the first, second and intermediate layers (6-8) gives the soldering portion (5) a composition corresponding to the eutectic gold-tin composition. The bonding-bump (1) may be manufactured by depositing a titanium seed layer onto the circuit element (10), removing portions of the titanium layer where there are contact pads (P) on the circuit element (10), electroplating the layers and portions (2-8) constituting the bonding-bump (1), and removing the remaining portions of the seed layer. This bonding-bond technique is used to connect circuit elements in electronic devices. Such electronic devices are appropriate to be used in telecommunications, for instance in mobile terminals. |