A semiconductor device package includes a semiconductor device with a ball grid array having a first subset of solder balls composed of metallic solder, and a second subset of solder balls composed of a composite material that includes a polymer core surrounded by a solder layer. The solder balls of the second subset can have a lower elastic modulus than the solder balls of the first subset and resist cracking due to thermal stresses on the semiconductor device package. In one embodiment, at least a portion of the second subset of solder balls is located on the periphery of the ball grid array such that the first subset of solder balls may be surrounded, at least partially, by the second subset of solder balls.

A mask is formed over a first conductive portion of a conductive layer to expose a second conductive portion of the conductive layer. An electrolytic process is performed to remove conductive material from a first region and a second region of the second conductive portion. The second region is aligned with the mask relative to an electric field applied by the electrolytic process. The second region separates the first region of the second conductive portion from the first conductive portion. The electrolytic process is concentrated relative to the second region such that removal occurs at a relatively higher rate in the second region than in the first region.