US Patent 7839000 Solder structures including barrier layers with nickel and/or copper

An electronic device may include an electronic substrate, and an under bump seed metallurgy layer on the electronic substrate. A barrier layer may be provided on the under bump seed metallurgy layer so that the under bump seed metallurgy layer is between the barrier layer and the electronic substrate, and the barrier layer may include nickel and/or copper. Moreover, portions of the under bump seed metallurgy layer may be undercut relative to portions of the barrier layer. In addition, a solder layer may be provided on the barrier layer so that the barrier layer is between the solder layer and the under bump seed metallurgy layer.