Substrate dividing method

Abstract

A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

1 . A substrate dividing method comprising the steps of:
 irradiating a substrate with laser light while positioning a light-converging point within the substrate, so as to form a modified region due to multiphoton absorption within the substrate, and causing the modified region to form starting point region for cutting along a line along which the substrate should be cut in the substrate inside by a predetermined distance from a laser light incident face of the substrate; and   grinding the substrate after the step of forming the starting point region for cutting such that the substrate attains a predetermined thickness.   
     
     
         2 . A substrate dividing method according to  claim 1 , wherein the substrate is a semiconductor substrate. 
     
     
         3 . A substrate dividing method according to  claim 2 , wherein the modified region is a molten processed region. 
     
     
         4 . A substrate dividing method according to  claim 1 , wherein the substrate is an insulating substrate. 
     
     
         5 . A substrate dividing method according to  claim 1 , wherein a front face of the substrate is formed with a functional device; and
 wherein a rear face of the substrate is ground in the step of grinding the substrate.   
     
     
         6 . A substrate dividing method according to  claim 5 , wherein the step of grinding the substrate includes a step of subjecting the rear face of the substrate to chemical etching.