The Mechanism And Experimental Research Of Compound Machining Of Polyurethane Polishing Pad And Cluster Abrasive Brush Based On MR Effect

With the development of Microelectronics, the demand of semiconductor and ceramics is increasing, in order to make use of the special characteristics of these kinds of materials, we have to process these hard brittle materials. Usually, these semiconductor and ceramics are used as substrates, so they require high surface flatness, small enough surface roughness and less surface and sub-surface damage, therefore, a proper processing method is very important. Compound machining of polyurethane polishing pad and cluster abrasive brush based on magnetorheological effect, as a new processing method, combining the high efficiency of lapping based on cluster magnetorheological effect and the precision of polyurethane pad polishing process, has high material remove rate, small surface roughness and little surface and sub-surface damage. The paper studied the processing mechanism and the technical experiments of single crystal silicon chips, SrTiO3 ceramic substrates and AIN ceramic substrates, according to the Compound machining. The detail contents are as follows:Firstly, analyzed the specialty of processing mechanism of lapping based on cluster magnetorheological effect, the characteristics of polishing pad and its effects on processing. Combining the advantages of lapping based on cluster magnetorheological effect and polyurethane pad polishing process, established the processing principle model and developed the processing mechanism of compound machining of polyurethane polishing pad and cluster abrasive brush based on magnetorheological effect. Researched the impact of the size of particles, the adaptability of abrasive particles and magnetic particles on compound machining.Secondly, evaluated and improved the ingredient of MR processing fluid from the point of stabilizer. Chose single crystal silicon chips, SrTiO3 ceramic substrates and AIN ceramic substrates as the representatives of hard and brittle materials, then researched them with single factor experiment, checked the workpiece surface roughness and the material removal rate, and on this basis, researched the effect exerted by process parameters on compound machining. Thirdly, the type of abrasives plays an important role on the processing effects, most researches only studied one single kind of abrasives in processing, but usually, one kind of abrasives can't meet the demand of machining, so this paper came up with the mixed abrasives of compound machining, and studied the impact of abrasive particles on compound machining from the view point of single type of abrasives and the mixture of two kinds of abrasives.Finally, analyzed the workpiece errors by the result of lapping plate wear, then optimized the plate from three aspects:the structure of plate, model of motion and ATA RAID. Roughed the surface of lapping plate uniformly according to the mechanism and model of compound machining, then established the processing model of rough lapping plate, studied the technical experiments and explored this new machining method.