Mechanism Research Of Ultrasonic Elliptic Vibration Assisted Fixed Abrasive Polishing Of Silicon Wafer

Silicon wafe is the most common substrate material for integrated circuit(Integrated Circuit,IC),and its height of surface quality directly affect the performance of IC chips.The increasing demand of IC in modern society,and its performance and integration requirements are getting higher and higher,to increase the output of IC chips,reduce the manufacturing cost of the device,the size of the silicon wafer tends to large diameter;Meanwhile,the increasing of IC integration put forward higher requirements on the surface of silicon wafer quality,which ruquires the wafer surface more and more flat,etching line thinner and thinner,these requirements have brought a lot of difficulties to silicon wafer processing,especially to the polishing process.However,the traditional machining methods of free abrasive polishing silicon wafer are generally inefficient and pollute the environment and other issues,therefor people constantly explore new processing technology to adapt to large size and high quality silicon wafer surface processing requirements.The application of fixed abrasive polishing technology well solved the problems that existing in the process of traditional free abrasive polishing,such as low material removal rate,waste of abrasive,pollution environmental and difficult to control the quality of polishing,and in view of this,ultrasonic elliptical vibration assisted machining has the advantages of improving machining efficiency?improving workpiece surface quality and prolonging tool life,and has been widely used in precision machining of hard and brittle materials.Based on this background,a new technique of ultrasonic elliptic vibration assisted fixed abrasive polishing of silicon wafer is proposed in this paper,and conduct the following research:First of all,the main components of polishing device and its polishing principle are introduced,and the surface formation,material removal and polishing process of polished silicon wafer were analyzed;Secondly,in order to better obtain the morphology and material removal rule of polished silicon wafer surface,the concept of track point density and its simulation model are proposed,the contrast simulation of the whole surface of polished silicon wafer has been carried out,and the corresponding experimental study has been carried out,the results show that the material of silicon wafer center is removed more.At last,in view of the very small amount of material removal on the silicon wafer surface,and it is very difficult to measure the value,in order to facilitate accurate measurement and reflect the actual situation of the polishing surface more correctly,the experiment and simulation research of the wafer ring region have been expand,obtained polished silicon wafer surface roughness and material removal change with feed speed,rotational speed and polishing force,and draw the following conclusions,UFP polishing process is more stable,more conducive to reducing the surface roughness of polished silicon wafers and improving the amount of material removal,the conclusions obtained can provide reference for further theoretical research and actual production.