(June 24, 2008) KYOTO, JAPAN &#151 Towa Corp., manufacturer of molding systems for semiconductor devices, anounced the development of a novel compression molding system that uses reportedly 60% thinner gold wires. The traditional traditional transfer molding process, in which the resin is poured across the substrate, require gold wires to be at least 25 µm in diameter to withstand the resin’s drag force without breaking. With Towa’s new process, the gold wires can be made as thin as 16 µm.

This novel compression molding technique is designed for large substrates on which 100-200 chips are mounted and packaged at the same time and then singulated. After the chips are mounted and connected with the gold wires, the substrate is dipped in a bath of a thermosetting resin in a special mold and then hardened with heat and pressure. The process is conducted under vacuum conditions to exclude air, gas and water vapor and ensure the resin does not form cracks.

In addition to the cost savings associated with using less gold, this procedure reportedly wastes no resin and is expected to facilitate the further miniaturization of circuitry and the stacking of chips.