Abstract: Disclosed is a method for efficiently separating a sapphire wafer serving as a substrate, on which semiconductor elements are formed, into unit chips by scribing the sapphire wafer, after grinding and lapping a rear surface of the sapphire wafer and then sand-blasting the sapphire wafer. The method includes the steps of: (a) grinding a rear surface of the sapphire wafer so that the sapphire wafer has a designated thickness; (b) lapping the rear surface of the ground sapphire wafer so that the sapphire wafer has a designated thickness; (c) polishing the rear surface of the lapped sapphire wafer so that the sapphire wafer has a designated thickness; (d) sand-blasting the rear surface of the polished sapphire wafer by uniformly blasting particles at a designated pressure during a designated time onto the rear surface of the polished sapphire wafer; and (e) scribing the rear surface of the sand-blast ground sapphire wafer.

Abstract: Disclosed herein is a method for cutting a semiconductor wafer having a semiconductor layer formed on the top surface thereof by units of a chip having a prescribed size. The method comprises the steps of lapping the bottom surface of the wafer so that the wafer has a prescribed thickness, and scanning a laser beam onto the bottom surface of the wafer to form a scribe line on the bottom surface of the wafer. The chip is defined by the scribe line. The method further comprises polishing the bottom surface of the wafer having the scribe line formed thereon, and dividing the wafer into a plurality of the chips along the scribe line. With the method of the present invention, contaminants, such as dust or spots, produced in the course of forming the scribe line is easily removed without an additional cleaning process.