The Robust Control And Fuzzy Fine Tuning For Wafer Level Flip-chip Equipment Motion Platform

At present,the flip chip packaging devices are becoming more miniaturization,higher density,more standardization and more modularization.It marks a higher performance for the dynamic response,stability and positioning accuracy of wafer level flip-chip equipment motion platform.High speed and high precision motion platform is a typical system with model uncertainty and disturbance uncertainty.The traditional PID control theory cannot achieve the satisfactory performance.But the robust control algorithm can solve the problem by a quantitative design for the uncertainty and disturbance of the controlled system.Using feedforward control can improve the dynamic response speed.Using the fuzzy fine tuning control algorithm to get the optimal parameters of the feedforward controller,improve position accuracy of the motion platform.A control algorithm is proposed to apply on wafer level flip-chip equipment motion platform,to improve the bonding quality of semiconductor chips.Contents of this paper are summarized as follows:1.Domestic and oversea research status of wafer level flip chip bonding machines and control systems are investigated and analyzed.The workflow of wafer level flip chip bonding machines are introduced.The positioning accuracy of motion platform is a major factor to affect the stability of the equipment and the consi stency of the packaging device.PID controller is used to study the high speed precision motion platform.A method is proposed to improve the positioning accuracy by analyzing the motion performance of the motion platform.2.Get the theoretical model of the controlled system by modeling the mechanism of the motor,motion platform and control system.Swept sine method is quoted to model the motion platform.Obtaining the amplitude frequency curve and phase frequency curve of the controlled system by the Fourier transform of the input and output data.System identification is used to get the mathematical model of the controlled system.3.A robust controller is designed based on the mathematical model of the motion platform system.Firstly,the uncertainty of the model and the way of selection for weighted functions is determined.Then,the robust controller by H-infinity theory is designed.Finally,the robust controller is simulated by MATLAB,and the stability quality of dynamic response and anti-interference ability of robust controller is verified.4.To mark the linear motor motion platform achieve high precision positioning,and improve the dynamic response speed of motion platform,a feedforward controller is added in the control system.The fuzzy logic is adopted to fine-tune the parameters of the feedforward controller,to ensure that the motion platform always keeps good motion performance during the movement,and improves the positioning accuracy of the motion platform.