Provided is a method of fabricating an ultra thin flip-chip package. In the above method, an under barrier metal film is formed on a bond pad of a semiconductor chip. Three-dimensional structured solder bumps are formed on the under barrier metal film, each of the solder bumps including a bar portion and a ball portion disposed at an end of the bar portion. The semiconductor chip including the three-dimensional structured solder bumps is bonded to a solder layer on a printed circuit board to complete a flip-chip package. According to the present invention, by employing the three-dimensional structured solder bumps, it is possible to lower the height of the solder bumps, thereby improving the reliability of an ultra thin flip-chip package.
