The present invention discloses an improved method for carry out a flip chip packaging process for attaching a semiconductor integrated circuit (IC) wafer having a plurality of input/output terminals, to a substrate. The method includes the steps of: 1) securely placing a plurality of solder balls on the substrate with each of said solder balls corresponding to a location of one of the input/output terminals on the integrated circuit wafer; 2) flipping the integrated circuit wafer for aligning each of the input/output terminals of the IC wafer to one of the solder balls; and 3) mounting the IC wafer onto the substrate for placing the I/O terminals on a corresponding solder ball and applying a reflow temperature for soldering the IC wafer to the substrate.