Method of adding filler into a non-filled underfill system by using a highly filled fillet

摘要

The present invention provides a semiconductor chip package with a fillet which contains a high percentage of a filler material by weight and a method of assembly with a semiconductor chip package for adding filler material to a non-filled or low-filled underfill system. The method of assembly produces a chip package where the concentration of filler material within the underfill material between the chip and the package substrate may be varied from location to location within the underfill material. The filler material increases the mechanical rigidity of the underfill material after it has hardened. Thus, using the approach of the present invention, the percentage of filler material may be increased in regions of the underfill material where the mechanical stresses require a greater mechanical rigidity. The present invention may be applicable to increasing the reliability of chip packages where the chip and the package substrate are separated by a gap about 25-50 microns wide.