US Patent 7345245 Robust high density substrate design for thermal cycling reliability

A semiconductor package for a die with improved thermal cycling reliability. A first layer of the package provides ball pads dispersed throughout. A second layer of the package provides signal traces. A high stress area associated with the corner of the dies is defined. Preferably the high stress area is defined as two ball pitches away from the corner of the die. Signal traces are routed away from the high stress area and in particular signal traces are routed away from the ball pads associated with the high stress to eliminate the cracks in the routed traces.