Flip-chip package with a heat spreader for high power dissipation LSI chips

Today's LSIs consume more power than their predecessors, so packages are required to cool them effectively. To make a package with a thermal resistance of less than 1 K/W, we developed a flip-chip C-BGA (ceramic-ball grid array) package with a large heat spreader soldered to the back of the flip-chip. Key fabrication techniques are to dispense resin after attaching the heat spreader, controlling the amount of resin dispensed, and forming an organic layer on the chip surface. In a heat cycle test, the package lifetime exceeded 1000 cycles. We also formed support balls to prevent the BGA-balls from collapsing under the heavy weight of the package.