On Optimization Design Of Precision For Flip Chip Bonder

Flip chip bonder is a critical equipment for the flip chip in the packaging process line,which can connect the bumps in the planar array between the chip and the substrate, whoseworking accuracy directly affect the yield, reliability and manufacturing costs of flip chip.Precision design is an important link in the designing process of flip chip bonding machine.However during the research and development of IC packaging equipment, domesticprecision design mostly adopt modeled on the analogy and experience design, which can’twell matching the cost and performance of packaging equipment. On the basis of relatedresearch at home and abroad, this article conduct the method study of precisionoptimization design for OCTOPUS-1000type of flip chip bonder. The main research workincludes the following several aspects.(1) The structure and error sources are analyzed. According to the composition of flipchip bonder system structure, this paper analyzes various error sources causing bondingprecision of flip chip bonder, The conclusion that the geometric error sources of flip chipbonder is key cause of error-making is obtained. Eventually it analyzes the motionmechanism of bonding machine in detail and finds geometric error of the movement partscausing bonding error.(2) The spatial error model is established. Based on multi-body system theory, thispaper takes flip chip bonder as an object to conduct systematic and comprehensive analysison movement precision. And it describes the topological structure and low-order bodyarrays of the bonding machine, adjacent body transformation matrix is derived under actualconditions. Ultimately, the spatial error model of flip chip bonding machine is established.The model reflects the relationship between the geometric error and overall bonding errorof different parts, which laid the foundation for the precision design of flip chip bonder.(3) The sensitivity analysis of space error is conducted. Based on the spatial errormodel of flip chip bonder, this paper adopts differential and matrix method to establish thegeneral model used for analyzing flip chip bonder sensitivity. Combined with thegeometric error data measured by Agilent laser interferometer, it calculates sensitivitycoefficient of geometric error and identifies critical geometric error that affects bondingaccuracy of flip chip bonder ultimately.(4) The precision optimization design of parts is completed. According to the resultsof error sensitivity analysis and the minimum cost of accuracy allocation, this paperestablishes the precision design model of flip chip bonder. Also, based on geneticalgorithm, the optimization design value of the geometric error is got through MATLAB genetic algorithm toolbox. And it verifies the optimal design results meet the accuracyrequirement of flip chip bonder.