Method of performing flip-chip underfill in a wire-bonded chip-on-chip ball-grid array integrated circuit package module

摘要

An underfill method is proposed for performing flip-chip underfill in an integrated circuit package of the type based on a WBCOCBGA (Wire-Bonded Chip-On-Chip Ball-Grid Array) construction which includes two semiconductor chips arranged in a chip-on-chip (COC) manner, wherein the underlying chip is electrically coupled to the substrate by means of wire bonding (WB), while the overlying chip is mounted in a flip-chip manner over the underlying chip and electrically coupled to the same by means of ball grid array (BGA) technology. The proposed method is characterized in the forming of an elongated dam structure over a preserved side surface area of the underlying chip beside the bonding wires connected to the underlying chip. During the dispensing process, the dispensed resin can fill into the gap under the overlying chip through capillary action while being prevented from coming in touch with the nearby bonding wires by the dam structure. As a result, the dispensed resin is prevented from flowing to the bottomside of the underlying chip, allowing the finished product of the WBCOCBGA-based package module to be more assured in quality and reliability than the prior art.