Abstract: A process for fabricating a solder bump having an improved geometry includes the steps of evaporatively depositing a first metallization system to form a post having a predetermined volume onto an integrated circuit having a passivation layer defining a die pad window, wherein the length of the post is greater than the width of the post, and wherein the length of the post extends beyond the die pad window over the passivation layer, and evaporatively depositing a second metallization system onto the post to form a cap also having a volume, wherein the first metallization system forming the post and the second metallization system forming the cap, when reflowed, form a eutectic solder bump.

Abstract: A method for dispensing underfill material between a flip chip bonded to substrate. The method requires an underfill injection port to be drilled through the substrate prior to reflow such that underfill material can be dispensed between the flip chip and substrate through the port. After reflow is completed, a pressurized pump delivers a predetermined amount of underfill under hydraulic pressure through the underfill injection port between the flip chip and substrate. Once injected, the underfill migrates between the flip chip and substrate via capillary action pushing out any air around the joints.