Evaluation Of Micro-pyramid Array Structured Monocrystalline Silicon Surface By Precision Grinding

In optical, automotive, aerospace, biomedical and solar energy projects, thesurface of the core components are manufactured to a high surface quality andhigh-precision micro-structure array, which can generate a new features. However,these high value-added parts are usually brittle materials, such as silicon, ceramic andglass, of which the machining is very difficult. At present, the micro-processing ofmicro-structure surface is mainly dependent on the light, chemical etching technology,which is difficult to control the shape accuracy. Because mechanical processingmethod has competitive advantages in structural consistency control, high processingefficiency and low cost, this study introduces a forming method with V-tip diamondgrinding wheel of200μm scale micro-pyramid array in monocrystalline siliconsurface, and explores the processing accuracy evaluation method of3Dmicro-structure.A CNC form truing technique by mutual-wear was developed for themicro-turing of V-tip diamond grinding wheel. During the truing experiment, thediamond wheel was driven along a V-shape straight interpolation to produce amutual-wear between the wheel and oilstone.And then, the CNC grinding machinedrove the V-tip diamond wheel to copy-engrave two groups of micro V-grooves onmonocrystalline silicon surface along level-reticulated cross paths. And themicro-pyramid array structured was formed.atter that, A while-light interferometerwas employed to measure the ground the ground micro-structured in opticalnon-contact detection,and the Iterative Closest Point algorithm (ICP) was employed tomatch the measuring3D coordinate point cloud to ideal micro pyramid-structuredsurface.Above this foundation, mathematical models were established as additionalanalysis and evaluation of V-groove angle, V-groove tip radius and pyramidal topradius.As a result, silicon crystal-orientation did less effect on grinding processing withthe regular processing crystal orientation in crystal face (100) of monocrystallinesilicon. This is because the crystal orientation of diamond grains randomly distributed in the grinding wheel surface. In addition, it was better to produce microsurface-structured on hard and brittle materials, such as silicon, by using a finer grainSD600diamond grinding wheel with dressed V-tip radius <20μm. And the aspectratio should increase from0.29, which processed by SD400diamond grinding wheel,to0.54, closer to the ideal aspect ratio of0.87.Although the micro pyramid-structured,that processed by SD600diamond grinding wheel, form error was only about3.4μm,its V-groove bottom and pyramidal top have very large form error (23.1μm-47.9μm)due to sharpness of wheel V-tip and the frangibility of micro pyramid top.In summary, the processing precision of micro-pyramid array structured formingby micro-grinding can be evaluated by the3D match mode.