The Tech Research Of Delay Forming FAB And Three Steps Bonding At First Bond Point In Copper WB Process

Background: The failure rates of original wire bonding type were about 1/4 to 1/3, some typical failure cases happened at first boning point in our production line, compared with golden wire copper wire being better electrical and mechanical performances and cost advantage.The author was responsible for the copper wire bonding in the practical work and studied it, found that there are many problems needed to be solved. In 22μm copper wire processes, for example, there had been key parameters not stable, virtual welding, with copper ball problems such as oxidation and lift ball bond, etc. Throughout checking the related papers, analyzing the bonding failure types and production data records, I paid much time and efforts on three parameters which are FAB forming delay time, Ultrasonic power and Bonding force. I defined final parameters spec. based on many experiments into optimizing the bonding qualities. With these efforts we have improved our final yield up to a satisfied level and increased about 1/5 production volume at the same time.This work has optimized the process window and put forward the scientific and reasonable solutions through a series of analyses and researches. Gradually solve the various problems in the copper wire bonding, and promote to the actual production application will be met. And the technology may provide the references for future packaging industry.