Toshiyasu Kawai

Removable tape using thermoplastic adhesive for QFN assembly process

The miniaturization of IC packages is progressing rapidly with the increasing demand for mobile electronic equipment. In particular, the demand for the QFN (quad flat non-leaded package), a lead frame type CSP, is increasing now. The productivity of the QFN assembly process can become much higher by using the MAP (molded array packaging) technology. In that technology, QFN support tape is a key material. It needs not only to attach well to the backside of the lead frame to avoid flash burrs in molding, but also to be removed easily from the lead frame and the molding resin with no residue after molding. For this usage, we have developed a new thermoplastic adhesive by optimizing the chemical structure and the characteristics. The new thermoplastic adhesive has a high elastic modulus, low amount of outgassing, and enough adhesive strength at high temperatures. Therefore, our RT series QFN support tape reveals: (1) good wire bondability, (2) no flash burr in molding, and (3) no residue after removal. These tapes contribute more to high yield and high productivity in comparison with the conventional sticky adhesive tape in the QFN assembly process.