Scrap wafer regeneration by precise abrasive jet machining with novel composite abrasive for design of experimentsg

Great quantities of silicon wafers have been used in the semiconductor industry, resulting in a shortage of raw materials required for wafer production. Unfortunately, conventional wafer regeneration processes still have some issues of machining properties. In this study a precise abrasive jet machining (AJM) method with a novel composite abrasive is employed to reduce the surface roughness of recycled wafers. Experiments designed using the Taguchi method was conducted for removal of patterns from the wafer surface to explore the impact of different processing parameters on surface quality and to optimize the combination of processing parameters. Experimental results show that the optimal parameters for achieving a smooth surface with minimum subsurface damage are composite abrasive coated SiC mesh of # 3000, impact angle of 30, stand-off distance of 70mm, jet pressure of 0.4 MPa, and platform revolution of 250 r/min. With these parameters, all surface patterns can be removed completely with machining for 5 min. The energy dispersive spectrometer (EDS) results prove that no residual elements exist on silicon wafer and surface roughness is reduced to 0.118 μm Ra, which contributes to surface improvement and shortens the post-processing time required for silicon wafer regeneration.