Flip-chip process using heat transfer from an induction-heating film

A new flip-chip technology to attach an IC chip directly to a substrate was studied using the heat transfer from an induction-heating film in an AC magnetic field. When applying a magnetic field of 230 Oe at 14 kHz, the temperature of a 600 μm-thick 5 mm × 5 mm Cu induction-heating film reached 250 °C within 60 s. The temperature of the glass substrate used in this process was kept below 118 °C at a distance of 1,350 μm from the Cu induction-heating film, which was maintained at 250 °C, implying that damage to a substrate can be minimized with the flip-chip process using heat transfer from an induction-heating film. Flip-chip bonding was successfully accomplished with the reflow of Sn-3.5Ag solder bumps by applying a magnetic field of 230 Oe at 14 kHz for 120 s to a Cu induction-heating film.