Servo System Position Control Of The Flip Chip Arms On A Flip Chip Bonder

With the rapid development of the semiconductor equipment industry,it is increasingly important to research on key components and core technologies of flip chip equipment.Positioning control of the flip-chip arms on a track-type flip chip bonder is studied in this thesis.The flip-chip arm module is a key component on flip-chip equipment to achieve a series of pick-up and flip-chip operations.Two difficulties exist when the flip-chip arm module is studied:First,the Z-axis and?-axis of the flip-chip arm are coupled.Movement of one axis applies varying disturbance and forces to another axis.This coupling causes model uncertainty.Secondly,as requested by flip-chip process,motions of the two-axes are planned simultaneously and delays exist in software and hardware.This causes the motion process of these two axes not smooth and lagging.It's hard to shorten the cycle time of the flip-chip arm and achieve accurate positioning.Because of above two difficulties,two direct drive axes of the flip-chip arm are not able to exert the maximum efficiency in terms of high speed and high acceleration with stable positioning.And the working efficiency and product quality of the equipment are reduced accordingly.In this thesis,the two direct-drive axes of the flip-chip arm are studied with servo control system and positioning control technology under high-speed and high-acceleration conditions.Two key indicators,"positioning time"and"positioning accuracy",are focused in this thesis to analyze the root causes of the difficulties in detail to meet both process and control of the flip-chip arm.Three steps,system modeling and identification,trajectory planning optimization and positioning control strategy,are conducted in this thesis to solve above two difficulties of the flip-chip arm module.As analyzed above,contents of this thesis are as follows:1.Detailed characteristics of the track-type flip-chip equipment is described,including its system composition,functional modules and process technology.And the servo control system structure of its key module flip chip arm is focused on.The process and control of the flip-chip arm module in this thesis is discussed.2.These two direct drive axes of the flip-chip arm are theoretically and experimentally modelled.The input and output data of the controlled object are obtained through a sine sweep experiment.Model parameters are identified using the frequency domain identification method,and the transfer function is obtained.Finally,system dynamic characteristics and mechanical resonance modes are analyzed and discussed.3.Trajectory planning is studied based on the characteristics of flip-chip arms under high acceleration.The characteristics of the typical trajectory planning are analyzed.Based on the system characteristics of the flip-chip arm,considering both the minimum time and the minimum impact criteria,the fifth-order S-curve planning is optimized to meet the requirements of the flip-chip arm servo system.Through experimental analysis,when the value of the weighting coefficient q in the optimized planning curve equation is larger,it means that the proportion based on the minimum impact criterion is larger,and the planning curve is with higher smoothness,but correspondingly the planned motion time is longer.Otherwise,if the value of q is smaller,the planned motion time is shorter to be optimal.4.For the Z and ? two-degree-of-freedom flip chip arm,it's combined with rigid and flexible couplings.A control strategy of H_?hybrid sensitivity robust controller is adopted to effectively solve the problem of model uncertainty caused by system coupling,which makes the system robust.The uncertainty analysis is performed based on the flip-chip arm system,a suitable weighting function for the sensitivity function is selected,and a robust controller based on the H_?mixed sensitivity is designed.Both the robust analysis experiment of flip-chip arm system under different working conditions and the dynamic response experiments of the flip-chip arm system under external interference are performed.Dynamic response experiments show that compared with the traditional PID controller,the flip-chip arm system which adopts H_?robust controller,has faster dynamic response,better steady-state settling performance,better anti-interference ability,and better robust performance.Moreover,the designed robust controller can make the flip-chip arm system work under different conditions,have good adaptability in the process of parameter change,and show good robustness.