A cryogenic under bump metallization (UBM) stack includes an adhesion and barrier layer and a conductive pillar on the adhesion and barrier layer. The conductive pillar functions as a solder wetting layer of the UBM stack and has a thickness. An indium superconducting solder bump is on the conductive pillar. The thickness of the conductive pillar is sufficient to prevent intermetallic regions, which form in the conductive pillar at room temperature due to interdiffusion, from extending through the entire thickness of the conductive pillar to maintain the structural integrity of the UBM stack. The indium (In) solder bump may be formed through electroplating, with the conductive pillar being copper (Cu) and the adhesion and barrier layer being titanium tungsten (TiW) and a thin seed layer of copper (Cu), or a layer of titanium (Ti).

A semiconductor device is provided with a semiconductor element having a plurality of electrodes, a plurality of terminals electrically connected to the plurality of electrodes, and a sealing resin covering the semiconductor element. The sealing resin covers the plurality of terminals such that a bottom surface of the semiconductor element in a thickness direction is exposed. A first terminal, which is one of the plurality of terminals, is disposed in a position that overlaps a first electrode, which is one of the plurality of electrodes, when viewed in the thickness direction. The semiconductor device is provided with a conductive connection member that contacts both the first terminal and the first electrode.

In a method of manufacturing a semiconductor device first conductive layers are formed over a substrate. A first photoresist layer is formed over the first conductive layers. The first conductive layers are etched by using the first photoresist layer as an etching mask, to form an island pattern of the first conductive layers separated from a bus bar pattern of the first conductive layers by a ring shape groove. A connection pattern is formed to connect the island pattern and the bus bar pattern. A second photoresist layer is formed over the first conductive layers and the connection pattern. The second photoresist layer includes an opening over the island pattern. Second conductive layers are formed on the island pattern in the opening. The second photoresist layer is removed, and the connection pattern is removed, thereby forming a bump structure.