An Experimental Study Of The Substrates Lapping And Its Damage For SiC Single Crystal Wafer

As a kind of advanced material. Silicon carbide (SiC), which has large band gaps, high critical breakdown field strength, high electron mobility and good thermal conductivity, is considered as an ideal material to manufacture the optoelectronic integrated device with high temperature, high frequency, high power and radioresistance. The growth of the epitaxial film and the manufacturing of electronic equipment require that the root mean square (rms) roughness of the final polished surface of SiC wafer should be at the nano-scale level. So, it’s important to study the processing technology of SiC single crystal wafer surface.Generally, the cutting surface of SiC wafer machined by the diamond wire cutting machine is uneven and has a large number of the saw marks. Lapping process can effectively remove the saw marks and the metamorphic layer of the cutting surface, and achieve the planarization of SiC wafer, so it is a crucial process to ensure the efficient machining of subsequent polishing process. Lapping is a conventional process for crystal machining, which is used to acquire the ultra-flat surfaee of SiC single crystal wafer.Lapping would inevitably bring about surface damage, which will severely affect the surface quality and must be removed by subsequent processing.A series of experiments of SiC single crystal wafer lapping are carried out to solve these problems in planarization process. The effects of abrasive, lapping pressure, lapping speed and some other factors on SiC single crystal wafer quality are studied. The relationship between surface roughness and material removal rate with processing parameters are obtained, and an optimized processes are achieved, which have been applied successfully in manufacturing of SiC single crystal wafer in the low volume. The surface topography and damage of SiC single crystal wafer with different conditions, are studied by scanning electronic telescope(SEM), KEYENCE VHX-600,OLYMPUS4000. The feature and production mechanism of the scratch, and the influencing factors of the scratch, such as abrasive, lapping wheel, processing parameters, are analysed, which will provide worthy reference for optimizing SiC single crystal wafer lapping and polishing process. The surface of SiC single crystal wafer without the scratch is obtained with W3.5diamond abrasive under certain conditions, using the methods of elastic pasting and floating load with fixed axis. And the method of decreasing scratch is researched.