A Ball Grid Array package having an increased fatigue life and improved conductive
pad adhesion strength, as well as providing sufficient wiring space within the
package, is disclosed. In particular, solder joints having a combination of mask-defined
and pad-defined solder joint profiles are formed using a mask having non-circular
elongated openings. The non-circular elongated openings of the mask have a major
axis and a minor axis, such that the dimension of the openings along the major
axis is greater than the diameter of the conductive pads, and the dimension of
the openings along the minor axis is less than the diameter of the conductive pads.
In addition, the major axis of the openings within the mask are selectively oriented
in the direction of highest stress for each solder joint within the package, while
providing ample wiring space therein.
