Abstract: A process of fabricating flip-chip packages is disclosed. First, a substrate having a carrying surface is provided. Next, a chip is provided, wherein the chip has an active surface, a plurality of bonding pads are disposed on the active surface and on each bonding pad a bump is disposed. Afterwards, the active surface of the chip is placed to face the carrying surface of the substrate, so that the chip is electrically connected to the substrate via the bumps and a flip-chip package is formed. Further, an underfill is filled between the substrate and the chip to encapsulates the bumps, while the processing temperature is kept between 100° C. and 140° C. for the underfill to be partially cured. Furthermore, the underfill is heated to be fully cured. By means of the process of fabricating flip-chip packages, the material uniformity after curing the underfill is solidly improved.