Method and apparatus for separation of workpieces and articles produced thereby

Patent metadata

Field	Value
Publication number	US-9610653-B2
Application number	US-201314032829-A
Country	US
Kind code	B2
Filing date	Sep 20, 2013
Priority date	Sep 21, 2012
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

The present invention is a method for separating a workpiece from a common substrate. It includes the steps of providing the workpiece, generating, within a beam source, a beam of laser pulses configured to modify a portion of the workpiece, determining a depth for creating a modified region based upon a characteristic of the workpiece and modifying a plurality of regions within the workpiece to form a plurality of modified regions. Modifying the plurality of regions includes directing the beam of laser pulses from an output of the beam source onto the workpiece, causing relative motion between the workpiece and the output of the beam source while directing the beam of laser pulses onto workpiece, and modifying a characteristic of the pulses of the beam upon generating a number of pulses which generally correspond to creating the modified regions to the determined depth.

First claim

What is claimed is:

1. A method, comprising:
providing a workpiece having a first surface, a second surface opposite the first surface and an interior between the first surface and the second surface;
generating a beam of focused laser pulses, the beam of focused laser pulses being characterized by beam waist at which laser pulses within the beam can attain a first fluence; and
forming a plurality of modified regions within the workpiece, each modified region extending from the second surface into the interior of the workpiece, wherein forming each modified region of the plurality of regions includes:
directing the beam of laser pulses onto the workpiece such that laser pulses within the beam pass through the first surface into the interior of the workpiece and towards the second surface, while causing relative motion between the workpiece and the beam of laser pulses, to modify a plurality of portions of the workpiece such that at least one of the plurality of portions of the workpiece is at the second surface of the workpiece and such that at least one modified portion of the workpiece is irradiated with a laser pulse characterized by a fluence less than the first fluence but sufficient to modify an additional portion of the workpiece; and
after irradiating the at least one modified portion of the workpiece with a laser pulse, modifying a characteristic of the beam of laser pulses such that at least one modified portion of the workpiece is not irradiated with a laser pulse characterized by a fluence sufficient to modify a portion of the workpiece.

2. The method of claim 1 further comprising determining a depth within the interior of the workpiece to which a modified region should extend based upon a characteristic of the laser beam.

3. The method of claim 1 wherein the characteristic of the beam comprises a pulse repetition rate.

4. The method of claim 1 wherein the characteristic of the beam comprises a pulse intensity.

5. The method of claim 1 wherein the characteristic of the beam comprises a pulse fluence.

6. The method of claim 1 wherein the characteristic of the beam comprises a spatial pulse spot shape.

7. The method of claim 1 wherein the characteristic of the beam comprises pulse spot size.

8. The method of claim 1 wherein the characteristic of the beam comprises an orientation of an optical axis along which the laser pulses impinge upon the workpiece at the first surface.

9. The method of claim 1 wherein the characteristic of the beam comprises pulse duration.

10. The method of claim 1 wherein the characteristic of the beam comprises temporal pulse shape.

11. The method of claim 1 wherein the characteristic of the beam comprises pulse wavelength.

12. The method of claim 1 wherein at least one laser pulse within the beam impinges the first surface at a spot having a non-circular shape.

13. The method of claim 1 , wherein the workpiece includes a strengthened glass workpiece.

14. The method of claim 1 , wherein at least one laser pulse within the beam includes light having a wavelength in the green range of the visible spectrum.

15. The method of claim 1 , wherein the beam of laser pulses has a Duty cycle greater than 10%.

16. The method of claim 15 , wherein the beam of laser pulses has a Duty cycle less than 50%.

17. The method of claim 1 , wherein at least one of the modified regions extends from the second surface of the workpiece into the workpiece by a height that is greater than 30% of the thickness of the workpiece.

18. The method of claim 17 , wherein at least one of the modified regions extends from the second surface of the workpiece into the workpiece by a height that is less than 60% of the thickness of the workpiece.

19. The method of claim 1 , wherein at least one of the laser pulses has a pulse duration greater than 18 ns.

20. The method of claim 1 , wherein at least one of the laser pulses has a pulse duration less than 20 ns.

21. The method of claim 1 , wherein the modified region includes an inclination angle, and the inclination angle is less than about 30°, as measured from a line.

22. The method of claim 21 , wherein the inclination angle is less than about 10°.

23. The method of claim 22 , wherein the inclination angle is less than about 1°.

24. The method of claim 1 , further comprising determining a depth within the interior of the workpiece to which a modified region should extend based upon a characteristic of the workpiece.

25. The method of claim 1 , wherein causing relative motion between the workpiece and the output of the beam source comprises causing relative motion between the workpiece and the output of the beam source such that the beam of laser pulses is translated through the first surface.

26. The method of claim 25 , wherein a distance between adjacent modified regions along the path is greater than 100 μm.

27. The method of claim 26 , wherein a distance between adjacent modified regions along the path is less than 300 μm.

28. The method of claim 1 , wherein modifying the characteristic of the beam of laser pulses comprises modifying the characteristic of the beam of laser pulses such that at least one modified portion of the workpiece is irradiated with a laser pulse characterized by a fluence that is less than the first fluence and that is not sufficient to modify a portion of the workpiece.

29. A method, comprising:
providing the workpiece having a first surface, a second surface opposite the first surface and an interior between the first surface and the second surface;
generating a beam of focused laser pulses, the beam of focused laser pulses being characterized by beam waist at which laser pulses within the beam can attain a first fluence; and
forming a plurality of modified regions within the workpiece, each modified region extending from the second surface into the interior of the workpiece, wherein forming each modified region of the plurality of regions includes:
directing a beam of focused laser pulses onto the workpiece such that laser pulses within the beam pass through the first surface into the interior of the workpiece and towards the second surface, while causing relative motion between the workpiece and the beam of laser pulses, to modify a plurality of portions of the workpiece such that at least one of the plurality of portions of the workpiece is at the second surface of the workpiece and such that at least one modified portion of the workpiece is irradiated with a laser pulse characterized by a fluence less than the first fluence but sufficient to modify an additional portion of the workpiece,

wherein at least one laser pulse within the beam includes light having a wavelength in the ultraviolet spectrum.

30. A method, comprising:
providing a workpiece having a first surface, a second surface opposite the first surface and an interior between the first surface and the second surface; and
forming a plurality of modified regions within the workpiece, each modified region extending from the second surface into the interior of the workpiece, wherein forming each modified region of the plurality of regions includes:
directing the beam of laser pulses onto the workpiece such that laser pulses within the beam pass through the first surface into the interior of the workpiece and towards the second surface, while causing relative motion be

Assignees

• Electro Scient Ind Inc

Inventors

• Zhang Haibin
• Shan Fang
• Rekow Mathew
• Zhang Min
• Simenson Glenn
• Xu Qian
• Brookhyser James
• Frankel Joe
• Darwin Michael
• Rundel Jack
• Pysher Matthew

Classifications

• B23K2103/50

  Inorganic materials other than metals or composite materials · CPC title

• B23K26/57

  the laser beam entering a face of the workpiece from which it is transmitted through the workpiece material to work on a different workpiece face, e.g. for effecting removal, fusion splicing, modifying or reforming · CPC title

• B23K26/0006

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K26/364 Primary

  for making a groove or trench, e.g. for scribing a break initiation groove · CPC title

• B23K2203/50

  Operations & Transport · mapped topic