# US 7,611,968 B2 · Wafer laser processing method and laser beam processing machine

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- Number: US 7,611,968 B2
- Document ID: US7611968B2
- Status: Granted
- Kind: B2
- Application number: 11/984,532
- Filed: 2007-11-19
- Published: 2008-05-29
- Granted: 2009-11-03
- Earliest claimed: 2006-11-24
- Assignees: Disco Corporation
- Inventors: Satoshi Kobayashi
- Web page: https://patentgrep.com/patent/US7611968B2

## CPC

- H10P 34/42: with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20)
- B23K 26/40: taking account of the properties of the material involved
- B23K 2103/50: {Inorganic materials other than metals or composite materials}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

A wafer laser processing method for forming deteriorated layers in the inside of a wafer having devices which are formed in a plurality of areas sectioned by a plurality of streets formed in a lattice pattern on the front surface along the streets by applying a laser beam along the streets, comprising: a first deteriorated layer forming step for forming a first deteriorated layer along the streets near the front surface of the wafer by applying a laser beam having a wavelength of 1,064 nm from the rear surface side of the wafer along the streets with its focal spot set to a position near the front surface of the wafer; and a second deteriorated layer forming step for forming a second deteriorated layer along the streets at a position closer to the rear surface of the wafer than the first deteriorated layer by applying a laser beam having a wavelength of 1,342 nm from the rear surface side of the wafer along the streets with its focal spot set to a position closer to the rear surface than the first deteriorated layer.

## Claims

### Claim 1

A wafer laser processing method for forming deteriorated layers in the inside of a wafer having devices which are formed in a plurality of areas sectioned by a plurality of streets formed in a lattice pattern on the front surface along the streets by applying a laser beam along the streets, comprising:
a first deteriorated layer forming step for forming along the streets near the front surface of the wafer by applying a laser beam having a wavelength of 1,064 nm from the rear surface side of the wafer along the streets with its focal spot set to a position near the front surface of the wafer; and
a second deteriorated layer forming step for forming a second deteriorated layer along the streets at a position closer to the rear surface of the wafer than the first deteriorated layer by applying a laser beam having a wavelength of 1,342 nm from the rear surface side of the wafer along the streets with its focal spot set to a position closer to the rear surface than the first deteriorated layer.

### Claim 2

A wafer laser processing method for forming deteriorated layers in the inside of a wafer having devices which are formed in a plurality of areas sectioned by a plurality of streets formed in a lattice pattern on the front surface along the streets by applying a laser beam along the streets, comprising:
a first deteriorated layer forming step for forming a first deteriorated layer along the streets near the rear surface of the wafer by applying a laser beam having a wavelength of 1,342 nm from the front surface side of the wafer along the streets with its focal spot set to a position near the rear surface of the wafer; and
a second deteriorated layer forming step for forming a second deteriorated layer along the streets at a position closer to the front surface of the wafer than the first deteriorated layer by applying a laser beam having a wavelength of 1,064 nm from the front surface side of the wafer along the streets with its focal spot set to a position closer to the front surface than the first deteriorated layer.