Effect Of Colloidal Silica On Chemical Mechanical Polishing Of Single Crystal SiC

The core of Electronic information manufacturing industry is the manufacture of microelectronics and optoelectronic components,It requires high integration and high performance of semiconductor chip.Therefore,how to make chip substrates achieve good machining accuracy and surface quality is the focus of today's reseach.Chemical mechanical polishing is the effective method to obtain the substrate substrate of ultra-precision machining.Single-crystal Si C as the third generation of semiconductor materials with high heat conductivity,high breakdown strength,high saturated electron drift velocity and forbidden band width is large,the mohs hardness is 9.2-9.5,second only to diamond,thus has big processing difficulty.The colloidal silica abrasive is coated with a layer of colloidal particles on the surface of nano-sized silicon dioxide,It can reduce the irregularity of abrasive grain shape and reduce the suface hardness,and minimize the damage on the surface of the workpiece in chemical mechanical polishing.And therefore is widely applied to the silicon wafer,planarization of precision optics surfaces.In this paper,firstly,the particle size and Zeta potential detection are tested with colloidal silica polishing solution from different manufacturers to analyze its stability.Compared with the effect of silicon sol from different manufacturers on the polishing of SiC chemical machinery,selecting the silicon sol products with better polishing effect.And then use different particle size of colloidal silica liquid polishing to do the Si C chemical mechanical polishing.Optimum composition of silicon sol polishing liquid by comparing the single-crystal Si C surface roughness after polishing and surface morphology.And under the condition of fenton reaction,the single crystal Si C was mechanically polished by silicon sol and W0.5 diamond polishing solution respectively.The surface morphology and roughness of single crystal SiC were detected by laser confocal microscope and white light interferometer,it is found that the abrasive polishing effect of the soft colloidal silica is worse,then the spectrum analysis,particle size analysis and Zeta potential analysis were performed on the colloidal silica containing different fenton reagents,combined with the effect of silicon sol polishing solution on single crystal Si C chemical mechanical polishing.The effect of fenton reaction environment on the stability of colloidal silica polishing liquid and its effect on SiC chemical mechanical polishing is to be explored.A single factor experiment was carried out on some major factors?abrasive concentration,H₂O₂,polishing pressure,rotating speed of the polishing liquid,polishing liquid flow?.The removal rate of single crystal Si C material and the change of surface machining quality is to be researched under different conditions,the optimize the parameters.The surface morphology,material removal rate and surface roughness of the single crystal Si C after polishing are optimized.The optimum process parameters are colloidal silica concentration is 30wt.%,the polishing pressure is 8kg,the concentration of H₂O₂ is 5%,the speed is 80r/min and the flow rate of the polishing liquid 60ml/min,the single crystal Si C is polished on the polyurethane polishing pad for 1 hour.Finally,surface roughness Ra0.221nm,a super-smooth surface can be obtained.