Design and Analysis of a Fast-Speed Flip-Chip Bonding System with Force Control

Abstract

Force sensing and control functions are very important for flip chip bonding systems for the reason of purchasing high-quality chip interconnection. But it is regrettable that, using the existing commercial technology and equipment, the bonding interconnection procedure is hard to be performed perfectly, specifically in the aspects of efficiency, accuracy and quality. There are many processes involved in the bonding interconnection procedure, so as to say, we need to take as far as possible every step and aspect into consideration. This paper proposed a highspeed flip-chip bonding system with force control, which can make the chips after alignment be bonded on substrate well as soon as possible. In the first place, benefited from the work of our predecessors, the active soft-landing (ASL) interconnection is realized by using the advantages of the monolithic force integrated flexible bonding device. However, the adopted flexure bonder is not enough to satisfy the high-efficiency flip-chip bonding requirement. Because the lightly-damping second-order spring system characteristic caused by the force detective part of the adopted flexure bonder. Secondly, based on the flip-chip bonding process, a flexure-based switch is designed to change the unidirectional stiffness of the bonder with the property of force detection for the purpose of reducing the vibration caused by the linear motor braking in the process. Thirdly, a novel closed-loop control strategy which can accommodate the requirements of position and force, namely hybrid position/force closed-loop (HPFC) control, with integrator composed of inertial filter (ICIF) is proposed to realize the high-efficiency force control under high-dynamic working conditions. By adopting these methods above, the bonding system can go through each step of chip bonding after alignment fleetest, and provide high-quality chip interconnection at the same time.