Abstract: In the flip-chip BGA semiconductor device of the present invention, a stiffener is bonded by means of adhesive on the surface of a substrate on which a semiconductor chip is mounted in the area surrounding the semiconductor chip, and gaps are provided between the substrate and the stiffener that each extend outwardly from positions that confront opposite sides of the semiconductor chip and that communicate with the ends of the substrate. These gaps can be formed by depressions that are provided in the substrate or in the stiffener.

Abstract: In accordance with the present invention, there is provided a method for depositing a lead-free tin alloy on a substrate. The substrate includes an external lead portion of a semiconductor device. The substrate is contacted with an electrolyte composition for depositing the lead-free tin alloy. Current is cyclically passed in a first direction through the electrolyte composition during ON-duty cycle portions to deposit the lead-free tin alloy on the substrate. The passing of current in the first direction through the electrolyte composition is cyclically prevented during OFF-duty cycle portions.

Abstract: In the flip-chip BGA semiconductor device of the present invention, a stiffener is bonded by means of adhesive on the surface of a substrate on which a semiconductor chip is mounted in the area surrounding the semiconductor chip, and gaps are provided between the substrate and the stiffener that each extend outwardly from positions that confront opposite sides of the semiconductor chip and that communicate with the ends of the substrate. These gaps can be formed by depressions that are provided in the substrate or in the stiffener.