Experimental And Surface Integrity Study On Single Crystal Silicon Nanometric Cutting

In recent years,as nano technology is growing rapidly,new higher demands have been put forward on the manufacturing of micro parts,not only for a smooth surface without damage,but also for the sub-surface integrity,that is,minimixing sub-surface damage.Considered that surface and sub-surface damages caused by the nanometric machining will exert certain effects on their physical mechanical functions and their service lives,machining mechanism of nanometric cutting and experimental process need to be investigated for improving the surface integrity of nanomanufacturing.This paper introduces the research status of nano manufacturing and base on the nanometric cutting device under SEM high vacuum condition,experiments were carried out on typical brittle material of single crystal silicon with a diamond cutting tool with nanometer edge radius.The main research contents are as follows:(1)Taken machining efficiency and machining quality into account,related studies were performed on electron backscatter diffraction(EBSD)sample preparation of AA6061 aluminum alloy and single crystal copper polished by focused ion beam(FIB),and appropriate paraments for sample preparation were found.And diamond cutting tool with 75 nm edge radius were shaped by FIB.(2)Base on the nanometric cutting device,we studied the thickness of the brittle-ductile transition of monocrystalline silicon with different crystal orientations and the reasons of the monocrystalline silicon plastic removal was discussed.The result showed that when cutting along the crystal orientation of(001)<100>,good processing surface will be gained when the cutting depth is less than 50 nm,while cutting along(001)<110> and(111)<10-1>,the cutting thickness shall be confined to no more than 90 nm.(3)Experiments were carried out for multiple cutting to monocrystalline silicon with different crystal orientations by using a diamond tool with 75 nm cutting edge radius and found that when cutting depth is less than the brittle-ductile transition thickness,the quality of machined surface changes periodically.When cutting depth is small,pitted surface can be repaired along with the following cutting;While cutting thickness is larger and brittle fracture occurred,the size and amount of pits changes periodically along with the following cutting,but the machined surface cannot be repaired.(4)The machined surface of single and multiple cutting and chips were studied by using EBSD and micro-Raman spectroscopy.The results show that EBSD can help to analyze the stress and strain of different cutting thickness and different depth of subsurface damage can be studied by using various electron beam energy.