Semiconductor substrate cutting method

Abstract

A semiconductor substrate cutting method which can efficiently cut a semiconductor substrate having a front face formed with a functional device together with a die bonding resin layer is provided. A wafer 11 having a front face 3 formed with a functional device 15 is irradiated with laser light L while positioning a light-converging point P within the wafer 11 with the rear face 17 of the wafer 11 acting as a laser light incident face, so as to generate multiphoton absorption, thereby forming a starting point region for cutting 8 due to a molten processed region 13 within the wafer 11 along a line along which the substrate should be cut 5 . Consequently, a fracture can be generated from the starting point region for cutting 8 naturally or with a relatively small force, so as to reach the front face 3 and rear face 17 . Therefore, when an expansion film 21 is attached to the rear face 17 of the wafer 11 by way of a die bonding resin layer 23 after forming the starting point region for cutting 8 and then expanded, the wafer 11 and die bonding resin layer 23 can be cut along the line along which the substrate should be cut 5.

1 - 8 . (canceled)  
     
     
         9 . A semiconductor substrate cutting method for cutting a semiconductor substrate having a front face formed with a plurality of functional devices into the individual functional devices, so as to manufacture a semiconductor device having the functional device, the method comprising the steps of: 
 attaching a protective member to the front face of the semiconductor substrate, such that the functional devices are covered;    irradiating the semiconductor substrate with laser light while positioning a light-converging point within the semiconductor substrate with a rear face of the semiconductor substrate acting as a laser light incident face after the step of attaching the protective member, so as to form a modified region, and causing the modified region to form a starting point region for cutting along each line along which the semiconductor substrate should be cut, the lines set like a grid running between the neighboring functional devices, inside by a predetermined distance from the laser light incident face;    attaching an expandable holding member to the rear face of the semiconductor substrate by way of a die bonding resin layer after forming the starting point regions for cutting;    cutting the semiconductor substrate and the die bonding resin layer from the starting point regions for cutting along each of the lines in the grid by expanding the holding member after attaching the holding member, so as to obtain a plurality of semiconductor chips each having a front face formed with the functional device and having a cut piece of the die bonding resin layer in close contact with a rear face thereof; and    mounting the semiconductor chip onto a support body by way of the cut piece of the die bonding resin layer in close contact with the rear face thereof, so as to obtain the semiconductor device.    
     
     
         10 . A semiconductor substrate cutting method according to  claim 9 , wherein the support body is a lead frame.  
     
     
         11 . A semiconductor substrate cutting method according to  claim 9 , wherein the holding member is expanded after the protective member is removed from the front face of the semiconductor substrate.