Ball grid array IC package and manufacturing method thereof

A ball grid array IC package comprising:

• a semiconductor chip having a plurality of chip pads;
• a substrate having ball lands;
• conductive balls electrically connecting the chip pads to the ball lands;
• and
• a plurality of inflatable polymer balls containing at least one of expandable material and being positioned between the semiconductor chip and the substrate, wherein the volume of the polymer balls under the influence of heat increases due to the expansion of the expandable material contained inside the inflatable polymer ball causing the gradual separation between the semiconductor chip and the substrate at a uniform gap and shaping the conductive balls into a substantially hourglass shape.

A ball grid array IC package comprising:

• a semiconductor chip having a plurality of chip pads;
• a substrate having ball lands;
• hourglass type conductive balls electrically connecting the chip pads to the ball lands;
• and
• an interval maintaining member for maintaining a uniform interval between the semiconductor chip and the substrate comprising a polymer ball comprising a material selected from the group consisting of an epoxy based resin and a polyimide based resin, and wherein the polymer ball may be charged with a material selected from the group consisting of air, gas, water, and oil.

A method of manufacturing a ball grid array IC package comprising the steps of:

• providing a semiconductor chip having a plurality of chip pads;
• forming a plurality of spherical conductive balls on the chip pads;
• providing a substrate including ball lands;
• attaching an expansive interval maintaining member to one of the semiconductor chip or the substrate;
• connecting the conductive balls to the ball lands;
• and
• expanding a volume of the interval maintaining member by carrying out a thermal treatment on the resulting structure so as to change the shape of the generally round conductive balls into one having hourglass features thereby causing the interval maintaining member to expand under heat, wherein the interval between the semiconductor chip and the substrate is formed by the interval maintaining member expanding under heat wherein the generally round conductive balls are extended into hourglass shape by the extension.