Study On The Key Technology Of Ultra-precision Chemical Mechanical Polishing Of SiC Single Chip

With the development and application of the photoelectron microelectronics technology, the third generation semiconductor material SiC has become the focus of the research, its excellent physical and chemical properties make it widely used in the new generation of electronic devices. As the devices performance requirements increasing, the demands for surface quality and planarization of wafer become higher and higher. Chemical mechanical polishing (CMP) technique is the most effective technology for global and local planarization of the wafer.The chemical mechanical polishing equipment is the core parts to obtain the super smooth surface and it shows the development level of CMP technology, the CMP technology and the CMP equipment are the essence in the wafer polishing processing. At present, the CMP equipment is not only a mechanical system, but becomes complicated automatization system integrating many relative technology and system, such as real time control of process, monitoring of end-point, on—line measure of wafer, applying of slurry and transortion of wafer, pad dressing, CMP post—cleaning and so on. In our country the production experiment equipment almost imported from abroad, so it is important to develop the CMP equipment in Our country.Combine the current development level of the CMP technology and equipment and the actual needs of enterprise production, we put forward to study the key technology of CMP and develop the small equipment. First based on the analysis of the CMP principles, for different kinematic forms, the mathematic models of the material removal rate on wafer in CMP are established. The effects of the kinematic forms and process parameters on material removal rate and material removal non—uniformity are analyzed, and the relations between the material removal rate and the process parameters in different the kinematic forms are revealed, and curve of the numerical simulation is carried out with Matlab. Then compare the two design scheme the linear reciprocating and the arc oscillating machine based on the material removal rate%material removal non—uniformity、the difficulty of the structure design、the cost of the equipment and then determine the linear reciprocating scheme and design it in detail. We innovatively proposed to combine the screw nut pair drive and the elastic element in pressure device, design of closed-loop pressure control system, realized the pressure of the fuzzy adaptive control and analyze the corresponding characteristics of system in the Matlab; Design the relative structure of the polishing head and buffing pads; analyze the on-line end inspection technology and the vacuum suction cup clamping technology; Finally, build the mode of the CMP machine and carry out the kinematics and dynamics simulation based on PRO/E-ADAMS, the motion parameters and mechanical characteristics of different points on wafer were measured and put out to verify the feasibility of the design scheme and the relative theoretical analysis.