Arrangement of pads and through-holes for semiconductor packages

Abstract

An arrangement of mounting pads on a substrate having segments, at least one of which has a plurality of mounting pads in a first row. Mounting pads of the first row are in connection with a corresponding offset through-hole oriented outwardly in the same general direction as a bisector definable for that segment, or oriented outwardly in the same general direction as a diagonal of the arrangement's outer shape. The segment defined can have a second and third row of mounting pads. The arrangement could include second, third, fourth, and so on, segments each with a plurality of mounting pads. Also included is an arrangement of Ball Grid Array (BGA) mounting pads on a circuit board for connection with electrical contacts of a BGA package, having: a first segment of a plurality of mounting pads in a first row with each mounting pad of the first row in connection with an offset through-hole oriented outwardly in the same general direction as a bisector definable for that first segment. More segments may be desired to accommodate a BGA package with a large number of leads. Additionally included, is a layer of a multi-layer circuit board having an arrangement of conductively-lined through-holes for electrical connection between layers. This arrangement has a first and second segment, each having a plurality of generally parallel rows of through-holes; the spacing between these two segments being generally greater than that between adjacent rows within either segment. The conductive lining of each through-hole is in connection with a mounting pad located on an outer side of the layer. Each through-hole is offset in an outwardly direction from its interconnected mounting pad.