Numerical Simulation And Experimental Research Of Slurry Film Characteristic In Chemical Mechanical Polishing

Chemical Mechanical Polishing(CMP) is a global planarization technique for large scale integrated circuit.Recently,the CMP is becoming more and more important and being used widely for high precision and global planarization.But,the CMP is developed in experience,and its creation,development,trend of development and use are finished not in academy but in industries.So,The researches systematically,especially theory research are very lack.Now, the researches for parameters of CMP technology,CMP theory model are becoming a very important subject.In the study of CMP mechanism,the research of slurry film has plays an important role in study of CMP mechanism.In the past,the most of slurry film model was built without considering the contact of wafer and pad,the deformation of wafer,roughness.In this paper,a three-dimensional hydrodynamic lubrication model and a three-dimensional partial film hydrodynamic lubrication have been developed according to three types of the contact of wafer and pad.The three-dimensional hydrodynamic lubrication model is based on the Reynolds equation and Reynolds boundary condition,and the deformation of wafer that has effects on lubrication performances of slurry film is considered.The slurry minimum film thickness,load-resistant of slurry film and tilted angle of the wafer have been obtained in solving the lubrication model.At the same time,there is an analysis on influences of load and speed of polish to minimum film thickness,tilted angle of the wafer.In the CMP,the roughness can produce great influences on lubrication performances of slurry film for the contacting of pad and wafer.The partial film lubrication mode has been presented based on three-dimensional hydrodynamic lubrication model,and considered the press flow factor and shear flow factor caused by the roughness.This model is based on the average Reynolds equation and Reynolds boundary condition,and the factors that have effects on lubrication performances of slurry film is considered,such as deformation of the wafer, roughness of the wafer and the pad are considered.The average slurry film thickness, load-resistant,tilted angle of the wafer have been obtained by solving the lubrication mode in finite element and have been analyzed influences on load,speed,roughness,deformations of the wafer.In addition,in the paper,a laser induced fluorescence technology is presented and the LIF experimental device is built for visualizing research to CMP.Using the experimental device,the slurry fluorescence intensity photos can be obtained.These fluorescence intensity photos can give the slurry film thickness information by image processing.At last,in the paper,it is found that the conclusions are similar by comparing the experiment data with numerical data.So,the models are reliable.