Abstract: A wafer processing method for processing a wafer having a substrate and a device layer formed on a front side of the substrate includes forming a mask on a back side of the wafer, so as to form an etched groove along each street through a thickness of the substrate from the back side of the wafer, performing plasma etching from the back side of the wafer through the mask to the substrate after forming the mask, thereby forming the etched groove in the substrate along each street so that the etched groove has a depth equal to the thickness of the substrate, and applying a laser beam to the device layer along each street from the front side of the wafer before etching and mask forming, thereby forming a device layer dividing groove corresponding to the etched groove along each street.

Abstract: A wafer processing method for processing a wafer having a substrate and a device layer formed on a front side of the substrate includes forming a mask on a back side of the wafer, so as to form an etched groove along each street through a thickness of the substrate from the back side of the wafer, performing plasma etching from the back side of the wafer through the mask to the substrate after forming the mask, thereby forming the etched groove in the substrate along each street so that the etched groove has a depth equal to the thickness of the substrate, and applying a laser beam to the device layer along each street from the front side of the wafer before etching and mask forming, thereby forming a device layer dividing groove corresponding to the etched groove along each street.