Blasting of Affected Layer of Silicon Surface Sliced by Wire EDM
Polycrystalline ingot slicing by wire electric discharge machining (W-EDM) has been investigated to reduce kerf loss and wafer thickness. In order to use the sliced wafers for semiconductor devices, the modified surface layer induced by W-EDM must be removed. In this paper, we have demonstrated the elimination of the layer by abrasive blasting. Three types of abrasives were blasted at a speed of 100 m/s. The surfaces blasted with WA #1000 and GC #1000 were smoother than that sliced with a wire saw. The modified layer induced by W-EDM slicing could be removed by blasting with WA #1000 while scanning the surface three times. Solar cells were fabricated using wafers with the blasted surface with an efficiency of 15.2%, which was almost the same as that of cells fabricated from the wire-sliced wafers.
Han Huang, Liangchi Zhang, Jun Wang, Zhengyi Jiang, Libo Zhou, Xipeng Xu and Tsunemoto Kuriyagawa
H. Hidai et al., "Blasting of Affected Layer of Silicon Surface Sliced by Wire EDM", Advanced Materials Research, Vols. 76-78, pp. 440-444, 2009