Patent ID: 7897488
Filing Date: 2011-03-01
Classification: B23K,H01L

Abstract:
1. A wafer dividing method for dividing a wafer into individual devices along a plurality of crossing streets formed on the front side of a substrate, wherein the devices are respectively formed in a plurality of areas partitioned by the streets, and the front side of the substrate is covered with a film, the wafer dividing method comprising: a modified layer forming step of applying a laser beam having a transmission wavelength to the substrate from the front side of the wafer along the streets so that a focal point of the laser beam is set inside the substrate, thereby forming a modified layer in the substrate along each street; a film dividing step of applying a laser beam having an absorption wavelength to the film from the front side of the wafer along each street to thereby form a laser processed groove for dividing the film along each street; a back grinding step of grinding the back side of the substrate of the wafer to thereby reduce the thickness of the wafer to a predetermined thickness; a wafer supporting step of attaching the back side of the wafer to the front side of a dicing tape supported to an annular frame after the back grinding step; and a wafer breaking step of applying an external force to the wafer by expanding the dicing tape supported to the annular frame, in the condition where the back side of the wafer is attached to the front side of the dicing tape, to thereby break the wafer along each street.