Pressure-driven method for filling underfill to flip chip

The present invention provides a pressure-driven method for filling underfill to flip chip. The method places a metal foil on top of a flip-chip die mounted on a substrate and uses a pressure plate to press on the metal foil so as to form a space among the metal foil, the die and the substrate. Then, packaging resin is filled into the space by pressure driving. Next, the die that has been attached with the metal foil and filled with resin is removed, and the next chip can be process for packaging. Because the chip filled with resin together with the metal foil is removed for curing, the packaging machine can package the next chip without waiting the resin to be cured. Therefore, the problem of sticky molding can be avoided, thereby increasing the production efficiency of the packaging machine. After the resin is cured, the metal foil may be kept or removed, depending on the actual requirement. If the metal foil is kept on the chip, it can be used to enhance heat dissipation, prevent electromagnetic interference and avoid electrostatic charge.