WAFER DIVIDING METHOD

• US 20080280421A1
• Filed: 04/17/2008
• Published: 11/13/2008
• Est. Priority Date: 05/11/2007
• Status: Abandoned Application

• Current Assignee: Disco Corporation
• Original Assignee: Disco Corporation
• Inventors: Nakamura, Masaru
• Application Number:
  US12/105,020
• Publication Number:
  US 20080280421A1
• Time in Patent Office: Days
• US Class Current: 438/462
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/53 for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
• CPC Class Codes: B24B 7/228 for grinding thin, brittle parts, e.g. semiconductors, wafers grinding edges of thin, brittle parts B24B9/065
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/6836 Wafer tapes, e.g. grinding or dicing support tapes adhesive tapes in general C09J7/20
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 2221/68327 used during dicing or grinding
• CPC Class Codes: H01L 2221/6834 used to protect an active side of a device or wafer

Abstract

A wafer dividing method that includes a modifying layer forming step in which a laser beam with a wavelength that can pass through the wafer is focused on the inside of the wafer from a rear surface side thereof, and applied along the street to form a modifying layer having a thickness corresponding to at least a device-finishing thickness from the front surface of the wafer; a rear surface grinding step in which an area, corresponding to the device area, of the rear surface of the wafer subjected to the modifying layer forming step is ground and formed to have a thickness corresponding to the device-finishing thickness and to have an annular reinforcing section at an area corresponding to the outer circumferential redundant area; a reinforcing section cutting step in which the wafer is cut along the inner circumference of the annular reinforcing section; a wafer support step in which the rear surface of the wafer whose annular reinforcing section is cut is stuck to a dicing tape attached to an annular frame; and a wafer rupture step in which an external force is applied to the wafer stuck to the dicing tape to rupture it along the street formed with the modifying layer.

Claims

1. A wafer dividing method of dividing a wafer along a plurality of streets arranged in a lattice pattern, the wafer having a device area formed with devices in a plurality of areas sectioned by the streets and an outer circumferential redundant area surrounding the device area, the method comprising:

a modifying layer forming step in which a laser beam with a wavelength that can pass through the wafer is focused on the inside of the wafer from a rear surface side thereof, and applied along the street to form a modifying layer having a thickness corresponding to at least a device-finishing thickness from the front surface of the wafer;

a rear surface grinding step in which an area, corresponding to the device area, of the rear surface of the wafer subjected to the modifying layer forming step is ground to have a thickness corresponding to the device-finishing thickness and to have an annular reinforcing section at an area corresponding to the outer circumferential redundant area;

a reinforcing section cutting step in which the wafer subjected to the rear surface grounding step is cut along the inner circumference of the annular reinforcing section;

a wafer support step in which the rear surface of the wafer whose annular reinforcing section is cut is stuck to a dicing tape attached to an annular frame; and

a wafer rupture step in which an external force is applied to the wafer stuck to the dicing tape to rupture the wafer along the streets formed with the modifying layer.

2. A wafer dividing method of dividing a wafer along a plurality of streets arranged in a lattice pattern, the wafer having a device area formed with devices in a plurality of areas sectioned by the streets and an outer circumferential redundant area surrounding the device area, the method comprising:

a rear surface grinding step in which an area, corresponding to the device area, of the rear surface of the wafer is ground to have a thickness corresponding to a device-finishing thickness and to have an annular reinforcing section at an area corresponding to the outer circumferential redundant area;

a modifying layer forming step in which a laser beam with a wavelength that can pass through the wafer is focused on the inside of the wafer from a rear surface side thereof, and applied along the street to form a modifying layer having a thickness corresponding to at least the device-finishing thickness from the front surface of the wafer;

a reinforcing section cutting step in which the wafer subjected to the modifying layer forming step is cut along the inner circumference of the annular reinforcing section;

a wafer support step in which the rear surface of the wafer whose annular reinforcing section is cut is stuck to a dicing tape attached to an annular frame; and

a wafer rupture step in which an external force is applied to the wafer stuck to the dicing tape to rupture the wafer along the streets formed with the modifying layer.