Abstract: In a flip chip bonding method, polymer bumps are formed, using a bonding tool, on an IC chip, held via suction to the bonding tool. An insulating adhesive film is pressed onto the upper surface of a circuit board held via suction with a suction stage. Heat is then applied to bring the film into close contact with bond pads of the circuit board. At this point, the bonding tool is moved downward, bonding the polymer bumps to the circuit board electrodes. During the time of this downward movement, bonding of the polymer bumps to the circuit board bond pads can be achieved by piercing the insulating adhesive film with the polymer bumps, and it is found that strong bonding can be achieved with adequate reliability. This method eliminates the need for a process in which through-holes must be pierced in the insulating adhesive film to accommodate the polymer bumps.

Abstract: The invention provides a flip chip mounting process in which a layer of electrically insulating adhesive paste is applied on a substrate having bond pads, covering the bond pads with the adhesive. Electrically conductive polymer bumps are formed on bond pads of a flip chip to be bonded to the substrate, and the polymer bumps are at least partially hardened. The bond pads of the flip chip are then aligned with the bond pads of the substrate, and the at least partially hardened polymer bumps are pushed through the adhesive on the substrate to contact directly and bond the polymer bumps to the bond pads of the substrate. This process results in direct electrical and mechanical bonding of the polymer bumps between the chip and substrate bond pads, even though the adhesive film was applied on the substrate in a manner that covered the substrate bond pads. The polymer bumps displace the adhesive as they are pushed through it and expand laterally on the substrate bond pads.