The Research On Mechanical Characteristics And Structural Optimization Of The Flip Chip Bonding Head

With the rapid development of very large integrated circuit, flip chip bonder (FCB)becomes an important microelectronic package device based on flip chip bondingtechnology. Bonding head in FCB is one of the most important and the highest motionprecision functional components used to deal with the process of chip bonding. In thepractical work, the bigger deformation and residual oscillation are often appeared when thelarge impact load and cycle vibration force act on bonding head under the condition thatthe structure stiffness is weakness.This paper put the chip-to-wafter type high density flip chip bonding head designedby demestic enterprise as the research object. The mechanical characteristics of static anddynamic of bonding head are investigated by using the finite element software and modernoptimization design method. The structure optimization and analysis verification have beendone which aim at the key weak link of bonding head. The main research content in thispaper as follows:Firstly, the3D digital model and finite element model of bonding head are established.The flip chip bonding technology is introduced aimed at the actual structure of bondinghead in this paper. The overall structure characteristic of bonding head is analyzed. Thethree-dimensional digital model is established using Solidworks software. The simplifyprinciple and method of bonding head is given. The finite element model is established byusing ANSYS Workbench software.Secondly, the static and dynamic mechanical characteristics of bonding head areinvestigated. In this paper, the analysis project of static and dynamic characteristics ofbonding head are given. The static deformation of bonding head is calculated under theaction of gravity, inertia force and bonding force. The constraint modal characteristics ofbonding head are studied by using ANSYS Workbench software under the braking andnon-braking working condition.Thridly, the structure mechanical characteristic of weak link of bonding head isoptimized. According to the analysis result of static and dynamic mechanical characteristicof bonding head, the optimization method is proposed by combining design parameterfiltration based on sensitivity analysis and optimal solution extraction based on AnalyticHierarchy Process (AHP). The parameter sensitivity is calculated. The optimization mathematical model of picking arm is established. The multi-objective optimization ofpicking arm of bonding head is calculated and analyzed.Finally, the simulation calculation result and finite element model of bonding head areverified. In this paper, the constraint modal characteristic of bonding head under thesimplified assembly condition is investigated by simulating calculation and experiment test.The experiment modal test project of bonding head is given. The modal parameters ofbonding head are obtained by ANSYS Workbench simulation calculation and LMS andPolytec experiment test. By comparison the result of simulation and experiment, thecorrectness of simulation result and the accuracy of finite element model are verified.This paper is financially sponsored by the N0.2National Major Project of China,named “Chip to wafer type high density flip chip bonding equipment development andindustrialization”（Grant No.2012ZX02601） and National Natural Science Foundationof China, named “Method of standard tolerance model and measurement certificationbased on the new generation GPS”(Grant No.50865003).