Patent ID: 7419851

Claim:
A method of making a semiconductor chip assembly, comprising: providing a metal base, a routing line, a metal containment wall and a solder layer, wherein the metal base includes first and second opposing surfaces, the first surface of the metal base faces in a first direction, the second surface of the metal base faces in a second direction opposite the first direction, the metal containment wall extends into the metal base from the second surface of the metal base towards the first surface of the metal base and includes a cavity, the cavity extends into the metal base from the second surface of the metal base towards the first surface of the metal base and includes an opening that faces in the second direction, and the solder layer contacts the metal containment wall in the cavity; mechanically attaching a semiconductor chip to the routing line, wherein the chip includes a conductive pad; forming a connection joint that electrically connects the routing line and the pad; etching the metal base using a wet chemical etch, thereby reducing contact area between the metal base and the routing line and between the metal base and the metal containment wall; and providing a solder terminal that contacts the metal containment wall in the cavity and includes the solder layer.