Method of fabricating ultra thin flip-chip package

Abstract

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.

1 . A flip-chip package comprising: 
 a semiconductor chip including a bond pad formed on a semiconductor substrate and a passivation film pattern overlying the semiconductor substrate and exposing the bond pad;    a first under barrier metal film disposed on the bond pad;    a second under barrier metal film disposed on the first under barrier metal film;    a plurality of solder bumps disposed on the second under barrier metal film, each of the solder bumps including a bar portion and a ball portion formed at an end of the bar portion; and    a package substrate, wherein the bar portion of the solder bumps directly contacts the package substrate.    
   
   
       2 . The package of  claim 1 , wherein the first under barrier metal film is formed of a composite film including a titanium film and a nickel film stacked sequentially.  
   
   
       3 . The package of  claim 1 , wherein the solder bumps are formed of an alloy film including lead and tin.  
   
   
       4 . The package of  claim 1 , wherein the second under barrier metal film is a nickel film.