Package substrate with current flow shaping features

摘要

Techniques and structures for achieving a more uniform current density in solder ball contact areas for a ball-grid-array semiconductor package are presented. Current density may be made more uniform by introducing electrically non-conductive regions into one or more areas that form a dedicated power rail within a package substrate that is configured to be connected with a die. Additionally or alternatively, the number of μvias that connect each solder ball contact area with conductive areas within the package substrate may be individually tailored based on the desired current density at each solder ball contact area.

主权项

1. A package substrate for use with a die, the package substrate comprising:
a plurality of layers, wherein:
each of the layers in the plurality of layers includes a pattern of electrically-conductive material, andthe plurality of layers includes:
a) a die-interface layer including one or more die contact pads configured to interface with solder bumps of the die,b) a ball-grid-array-interface (BGA-interface) layer including one or more BGA contact pads configured to interface with solder balls, andc) one or more additional layers interposed between the die-interface layer and the BGA-interface layer; and a plurality of power rails, each power rail:
conductively connecting one or more of the BGA contact pads with one or more of the die contact pads, andincluding interlayer vias conductively connecting one or more areas of each of two or more of the layers, wherein:
at least one of the additional layers includes one or more electrically-nonconductive regions arranged to produce an electrical current density that is more evenly distributed within a given power rail when i) the die is installed and ii) power is applied to the die through the package substrate as compared with the electrical current density that is produced within the given power rail when i) the one or more electrically-nonconductive regions is instead electrically-conductive, ii) the die is installed, and iii) power is applied to the die through the package substrate.