Algorithm Research Of Wafer Film Thickness Measurement Based On White Light Reflection Spectrum

The manufacturing of chips is an extremely complicated and refined industry chain.Wafer polishing is located in the in several reciprocal processes in the industry chain.If there is a mistake,dozens of processes will be cancelled.As a result,high-quality wafer polishing not only is the key step for chip production,but also is the foundation to produce high-quality semiconductor chips.In polishing,real-time measurement of wafer film thickness is the priority to concern success of the entire polishing step.Measurement of the wafer film thickness is divided into the static measurement and dynamic measurement.Static measurement is the foundation of dynamic measurement,while dynamic measurement is the compilation of static measurement.In actual production,due to internal wafer pattern,impurities and oxidation technology,existing algorithms can't accurately measure the wafer film thickness.However,the improved methods only improve the measurement and polishing equipment,but they seldom get involved in the improvement on the measurement algorithm.By aiming at this problem,the author puts forward the brand-new improved measurement algorithm of wafer film thickness.On the basis of the original algorithm,the autonomous optimizing algorithm is introduced,thus this algorithm can improve the algorithm parameters in accordance with the physical truth of measurement,so as to achieve a goal to improve algorithm.In this way,this algorithm will be suitable for detection of wafer film thickness with different batches and diverse impurity contents.On the basis of the original measurement theory,the author in this thesis introduces three autonomous optimizing algorithms,including simulated annealing,classical inheritance and simulated annealing inheritance,constructs the experimental platform of static measurement,and tests the effect of the improved algorithm.The experimental results indicate that the introduction of three algorithms develops an improved effect on the measurement algorithm of the wafer film thickness.Moreover,simulated annealing inheritance among three algorithms has the best improved effect.