The resin molded chip size package (MCSP)

The resin molded chip size package (MCSP), consisting of a polyimide/Cu film carrier with metal bumps, has been developed. The CSP having area-array type electrodes connected with the printed circuit board has been developed by many semiconductor companies. We have developed a resin molded CSP. The encapsulant used for this application has also been developed; it is unlike the conventional liquid type or transfer mold type. The molding method is also new and has been indigenously developed. Two new molding methods were designed: 1) the resin-mold and the connection between the semiconductor-chip and the carrier tape with the metal bumps were simultaneously carried out using the newly developed thermo-adhesive polyimide coated on the carrier tape before the connection; 2) this approach involved laminating the sheet on the semiconductor-chip with the new polyimide adhesive. The encapsulation and the reliability of MCSP were investigated and found to be excellent (resistance to corrosion, heat and stress), equal or superior to that of the conventional surface-mounted devices.