Preparation And Performance Experimental Study Of Polyurethane-based Magnetorheological Elastic Polishing Pad

With the rapid progress of industries such as electronics,communication engineering and microelectronics,the semiconductor devices of key components require not only high flatness,ultra-smooth,sub-nanometer surface roughness and no sub-surface damage.Polishing is a part of the ultra-precision processing of semiconductor devices,and the properties of its abrasive materials directly affect the surface processing accuracy of semiconductor materials.At present,in the field of polishing,traditional polishing abrasive tools have problems such as low processing efficiency,low adaptability to complex curved surfaces,poor self-sharpening of abrasive tools,and inability of intelligent control of polishing abrasive tools.In response to the above problems,this paper proposes a polishing pad made of polyurethane magnetorheological elastomer,and demonstrates the polishing performance of this new type of abrasive tool through experiments,simulation and mechanism analysis.The contents of this article are summarized as follows:(1)Analyzed the research status at home and abroad in the field of semiconductor material polishing,summarized the technical requirements for polishing in the field of ultra-precision machining and the deficiencies of existing polishing techniques,and reviewed magnetorheological changes.Based on the above analysis,a new idea of using polyurethane magnetorheological elastomer to make polishing pads to process semiconductor materials is proposed based on the domestic and foreign research status of elastomer preparation,performance characterization and related applications,and its research significance in this topic is analyzed.(2)Based on the magnetorheological effect theory of polyurethane magnetorheological elastomers,an experimental study on the preparation process of magnetorheological elastomer polishing pads was carried out,a set of polishing pad forming equipment was developed,and the magnetorheological elasticity of polyurethane was determined through process experiments.The raw materials and proportions of the body are used to prepare polyurethane-based magnetorheological elastic polishing pads with different abrasive particle concentrations,different carbonyl iron powder concentrations and different magnetic field conditions by using magnetorheological properties.(3)Based on the magnetorheological properties of magnetorheological materials,the magnetic properties of polyurethane-based magnetorheological elastomers were studied,and the microscopic morphology and composition of the polyurethane magnetorheological elastomers under different working conditions were observed.The magnetic hardness of the polyurethane-based magnetorheological elastomer,and the experimental research on the magneto-mechanical properties of the polyurethane magnetorheological elastomer,analysis and discussion of the rheological properties,magneto-friction properties and resistance of the polyurethane magnetorheological elastomer scratch performance.(4)Designed and built a set of experimental devices suitable for polishing workpieces with polyurethane-based magnetorheological polishing pads.Using finite element software,the magnetic field distribution of the magnetic field generator at different positions from the polishing pad was simulated,and the size of the magnetic field was analyzed.The relationship with the distance between the polishing pad and the magnetic field.The material removal function of the polyurethane magnetorheological elastic polishing pad was established,the magnetorheological polishing mechanism was analyzed and discussed,and the influence of the magnetic field,polishing speed and polishing pressure on the polishing effect was explored through the polishing experiment of silicon carbide materials.Combined with the magnetomechanical properties of the polyurethane-based magnetorheological elastic material itself,the excellent polishing performance of the polyurethane magnetorheological polishing pad and its application prospects in the polishing field are summarized.