Dam guide to assist underfill process and heatspreader to chip package
Original Publication Date: 2003-Jun-25
Included in the Prior Art Database: 2003-Jun-25
Related PeopleOther Related People:
be made easier; where the transfer of mold compound is controlled and easily dispensed onto the substrate and silicon die. NOVELITY: An integrated circuit chip package according to this invention includes an integrated circuit chip mounted on to a substrate by multiple solder bumps. A mold compound is used for underfilling the air gaps in between the chip and substrate. An integrated circuit chip package is formed after placing the integrated circuit onto the substrate and reflowed with eutectic solder paste. A rectangular or square dam frame (depending upon the die size and package dimensions) is glued onto the substrate. This Copper or Aluminium dam frame varies in width and height according to the die thickness and package respectively and size. This Copper dam stands as a barrier assisting the mold to encapsulate the die and prevents the mold from overflowing. Once the dam region is filled with mold encapsulating the die and solder bumps, A Copper heatspreader is glued onto the Copper Dam and mold by a con-ductive adhesive. Thus sealing the mold and the die for as a strong reliable bonded encapsulation and dissipating heat out of the chip package. This invention is highly reliable because it enables the silicon die to perform to its utmost limits and has a very high thermal performance in a 3 dimensional pattern. PACKAGE BUILD: After the silicon die is solder bumped onto the substrate the Copper frame is glued onto the substrate at the exact location so as to enable molding encapsulation. The mold feed is controlled by the dispencing needle resevoir, so that it does not overflow the dam barrier. Once the mold compound gets filled and reaches the dam barrier top edge completely encapsulating the die and solder bumps, the molding process is done. Upon curing the mold is baked and cured. The heatspreader is mounted onto the die area and dam barrier area with conductive adhesive.