Abstract: Semiconductor devices are described that have an extended under ball metallization configured to mitigate dielectric layer cracking due to stress, particularly stress caused by CTE mismatch during thermal cycling tests, dynamic deformation during drop tests, or cyclic bending tests, and so on. In an implementation, the semiconductor package devices include an integrated circuit chip having a solder ball and under ball metallization, formed on the integrated circuit chip, which is configured to receive the solder ball so that the solder ball and the under ball metallization have a contact area there between, wherein the area of the under ball metallization is area greater than the contact area.

Abstract: An integrated circuit including solder balls containing an elastic or resilient material core, a hard or rigid shell substantially enclosing the core, and an electrical contact layer substantially enclosing the shell. The elastic or resilient core serves as a stress buffer layer in a wafer level package (WLP) integrated circuit. The elastic or resilient material core may include an organic plastic material, such as a Divinilbenzene cross-linked co-polymer of relatively high resistance. This material has a relatively good elongation property so that it can effectively absorb forces exerted upon the integrated circuit by, for example, the flexing of a printed circuit board (PCB) or other structure to which the integrated circuit is attached. The hard or rigid shell serves to contain the elastic or resilient core and may include copper. The electrical contact layer serve to provide a good adhesive electrical contact to an under bump metallization (UBM) layer, may include a lead free, Tin-Gold (SnAg) material.

Abstract: Method for relieving stress in silicon microstructures by forming a silicide on the microstructures. Sensors comprising a stress-relieved silicon microstructure are also described.