Copper Wire Bonding Technology And Equipment Research And Applications

Wire bonding is one key process in the integrated circuit devices assemble, usually, the bonding wire is golden wire in the traditional assemble process. The golden wire is almost applied in all the advanced IC assemble process by its'better conductivity, elongation and chemical stability. However, with the gold-price's going up, the assemble process using the copper wire as the bonding wire gradually become the first choice in the industry, although, the two fatal weakness which are higher hardness and easy oxidation for copper wire result in the bonding process in the instability status, as a result, the bonding ball is easily becoming oxidation in EFO and the failure mode also easily occur at the first bonding as pad peeling, silicon crater and AL squeeze out; further more, most old wire bonding equipment is golden wire process although many equipment manufacturer can install the copper wire machine. So, if developing the copper wire process, the current wire bonding equipment must be updated, which is another obstacle to expand the copper wire process. In this thesis, the above-mentioned two issues has been studied which are put in practice as purpose, the experiment data and theory analysis are used as the judgment, through the upgrade for the copper wire equipment and the deep analysis for the copper wire process failure mode, the novel materials and process are explored and researched for the two issue. The main research contents as follows:1.Detailed discussed the bonding wire material's type, applicable situation, three type wire bonding technology's difference and introduced the market status for the copper wire, the copper wire's cost advantage and the bonding ability advantage.2.Detailed researched the technical condition upgrading the wire bonding equipment from golden wire process to the copper wire process, especial the bonding ball anti-oxidation design, wire clamper calibration and EFO system upgrade, then studied the whole upgrade procedure and the related item especial the total equipment calibration.3.Detailed explored the critical failure mode and the formation mechanism as pad peeling ,silicon crater and Al squeeze out, then investigated the Air Free Ball's affection factor and its'influence on the copper wire bonding process, at last researched failure mode affection factor and key parameter for the first bond and the second bond.4.Discussed the two destructive test methods, result analysis to evaluate the copper wire bonding quality and the future develop trend for copper wire bonding.