IMPROVED SOLDER BALL JOINT

摘要

An improved interconnection ball joint for a ball grid array integrated circuit package includes a substrate base having a first surface to which an integrated circuit die is affixed, and an opposite second surface. A metallized via extends through the substrate. The via has a central hole which extends through the substrate. The hole is plugged with a flexible nonconductive material, such as epoxy solder mask material. A metallic interconnection ball land is on the second surface of the substrate, integral with the metallized via and adjacent to the hole and the plug of nonconductive material. A solder interconnection ball is formed on the land, opposite the via and the plug of nonconductive material. A metal-to-metal annular bond is formed at the joint between the interconnection ball and the land around the plug of nonconductive material in the center of the via. The joint has an unexpectedly high shearing strength, and resists cracking, which reduces risks of a electrical connectivity failure at the joint. Location of the interconnection ball directly opposite the via allows miniaturization of the package.