Ball grid array package with protective circuitry layout and a substrate utilized in the package

Abstract

Disclosed is a BGA package with protective circuitry layouts to prevent cracks of the bottom circuit in the specific area of the substrate leading to package failure and to enhance packaging yield of BGA packages. A chip is disposed on the upper surface of the substrate. A chip projective area is defined inside the bottom surface of the substrate and is established by vertically projecting the edges of the chip on the upper surface to the bottom surface of the substrate. At least an external contact pad vulnerable to thermal stress is located within the chip projective area. A protective area and a wiring area are respectively defined in the chip projective area at two opposing sides of the external contact pad. A plurality of protective mini-pads are arranged in a dotted-line layout and disposed in the projective area to partially surround the external contact pad to avoid thermal stress concentrated on the protective area and to further prevent circuitry cracks in the package structure.