Research On The Double-Sided Polishing Mechanism And Process Optimization For Silicon Wafer

The semiconductor material silicon wafer is processed efficiently toget the ultra-smooth surface for the demand of the rapid development of themicroelectronic and information technology. It is the research tendency toget the smooth and non-traumatic surface of the silicon wafer with highefficiency in the field of the ultra-precision polishing technology. It issignificant to develop the ultra-precision double sided polishing machineand optimize the double sided polishing process of the silicon wafer inChina.According to the design demand of the ultra-precision machine, theintegrated design proposal of the double sided polishing machine was putforward in the paper. The control system of the double sided polishingmachine was developed. The hardware of control system and interactiveaction interface were introduced in detail.The mathematic model of planetary double sided polishing kinematic locus was set up through discussing the kinematic relation among the wafer,polishing pad and the carriers. The software Matlab was adopted to analyzethe influence of the kinematic locus on surface quality in the differentposition, rotational speed of polishing pad and ratio of transmission. Thepolishing uniformity function was set up. The key parameters whichinfluence the polishing uniformity were studied by the method ofsimulation.The process parameters such as the polishing pad and carrier rotationspeed, polishing press, polishing slurries etc. to affect the surface quality ofsilicon wafer, were also discussed in this paper. The experiment of doublesided polishing process was done in the new double sided polishingmachine. With the research and optimization of the polishing parameters,the precision polishing process with ultra-smooth and no traumatic surfaceof silicon wafer was achieved by the suitable polishing process.