Technical Study On Chemical Mechanical Polishing Of CVD Diamond Film

Diamond is widely applied in many fields due to its excellent performance in mechanics, thermodynamics, optics, acoustics and semiconductor. Chemical vapor deposition technology has advanced the growing rate and quality of diamond and the price has been reduced significantly. However, because of the limit of growing theory and technology, CVD diamond film usually has rough surface and polishing is required ahead of practical application.Existing planarization technologies mostly are unable to achieve ultraprecise maching of diamond with low scathing resulted. CMP(Chemical Mechanical Polishing) is considered to be one of the most prospective methods. In this thesis based on the analysis about existing problems of CMP of diamond, a technology of combining lapping and CMP with heating partly was proposed. The main contents are as follows:(1) The technology of combing lapping and CMP with heating partly was used to process diamond film. The results show that the surface roughness can be reduced from Ra13.3μm to Ra40nm quickly, and CMP can not only process the diamond film precisely, but also avoid warp and wear of plate induced by heating globally.(2) Key components of slurry were optimized. Six kinds of slurry with six different oxidants were analyzed and tested. K2FeO4 turns out to be best. It is proved that mutual action of mechanical action and chemistry plays an important role in material's remove through experiments.(3) Through single-factor experiments, effect of temperature, pressure and plate's rotate rate on polishing was investigated. Proper technic parameters were settled:temperature 50℃, pressure 266.7 kPa, plate rotate rate 70r/min. With these parameters diamond film was polished for 7 hours and the surface roughness reached Ra4.5nm.(4) The setup was designed and made for friction measurement of diamond film. Online measurements about friction and its discipline versus pressure, rotate rate and so on were conducted. Mixed lubrication between film and plate could be deduced. The relationship between friction and material removal rate was analyzed to make preparation for study on mechanism of chemical mechanical polishing diamond.