Cavity-down ball grid array plastic package preparation method

The invention relates to a cavity-down ball grid array plastic package preparation method. The method comprises the following steps of slot body forming, chip paster processing, bonding, film pasting,sealing, cutting channel forming, film peeling, and reballing. According to the invention, an isolating film is pasted in a reballing welding plate region; a chip, a bonding wire, and a welding plateare sealed and packaged at the same side of an IC carrier board by means of moulding; and then a sealing material and the isolating film on the welding plate are removed. Therefore, the sealing density, consistency, and flatness and the bonding strength with the IC carrier board are improved; the water absorption property after sealing is reduced; the reliability of the integrated circuit is improved obviously; and the high reliability requirement of the customer is met. According to the preparation method, with several kinds of processes like the laser process, the plasma process or the mechanical processing process,