109 Effects of Air and Surface Oxidation in Ultra-micro Cutting of Mono-crystalline Silicon

Abstract

Due to inereasing demands for mieroandlor high-precision parts, ultra-miert) cutting technologies hftve been developed at high speed, The importance of atmosphcre in micre cutting has beert reoognized morc and mora in Tecerit researches. This is because the effects of cuthng enyironments andlor surface oxidation ofa workpieee inerease when the scale of cuttirtg decreases, In this paper, based on the results of a series of cuttirig experimerrts, we discuss bow the atmospheric molecu!es affect the pertbrmance of microctnting. The cutting force, critical dqpth of eut and scratchcs fomied on the workpiece surface have been examined and compared between the resuks of cutting in air and those in yacuum environments.Tlie workpieces are silicon mono-erystals that have bcen exposed to air for various lerigths oftime after being cleaned with RCA method, The experimental results skow that brittlelductile trar:sition takes place with smaller depth of cut in air than in a vacuum. This impljes that thc briuleness of a silicon meno-erystal deereases in a vacuum.On the other han¢ from the comparison of results obtairred using a tool moving back and fbrth in air and in a vacuuml t't has also been found that cutting force decreases if atmospheric rnolecules are sandwiched betwecn a tool and chip durmg cutting. This could be because of thc lubrication effbct of the atmospheric molecules.

MD Simulation of Ultra-Micro Cutting of Monocrystalline Silicon with Effects of Air

“…It is seen in this figure that the normal cut- Fig. 9 An example of cutting forces measured in cutting experiment for cutting in air (7) Fig. 10 Relation between measured principal cutting forces F1 and F2 (7) ting forces Fn1 and Fn2 at the points B and B are almost the same, whereas the corresponding forces F1 and F2 in the horizontal direction are somewhat different.…”

“…9 An example of cutting forces measured in cutting experiment for cutting in air (7) Fig. 10 Relation between measured principal cutting forces F1 and F2 (7) ting forces Fn1 and Fn2 at the points B and B are almost the same, whereas the corresponding forces F1 and F2 in the horizontal direction are somewhat different. Using the data of F1 and F2 collected by repeating the cutting experiments in air and in a vacuum ((2.0 -4.0) ×10 −6 Pa), the relationship between F1 and F2 is shown in Fig.…”

“…It was derived rather based on a qualitative discussion described above and was used for verifying the effects of atmospheric molecules simply. Because of approximations adopted, this method may not give quite accurate results, however, it is possible to compare simulation result with experimental ones (7) qualitatively and even quantitatively to some extent. In the latter point of view, the validity of the method of potential modification used here in expression (1) could be examined by this comparison.…”

“…In order to investigate the effect of atmospheric molecules in microcutting, the authors carried out a series of microcutting experiments in air and in a vacuum by using silicon workpieces and diamond tools (7) . In Ref.…”