Method for adjusting ablation threshold

• US 20080160295A1
• Filed: 04/12/2007
• Published: 07/03/2008
• Est. Priority Date: 04/12/2006
• Status: Abandoned Application

• Current Assignee: Picodeon Ltd. Oy
• Original Assignee: Picodeon Ltd. Oy
• Inventors: Myllymaki, Vesa, Lappalainen, Reijo, Ruuttu, Jari, Pulli, Lasse, Makitalo, Juha
• Application Number:
  US11/783,840
• Publication Number:
  US 20080160295A1
• Time in Patent Office: Days
• US Class Current: 428/332
• CPC Class Codes: B23K 2103/40 Paper
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/1224 in vacuum
• CPC Class Codes: B23K 26/123 in an atmosphere of particular gases
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/60 Preliminary treatment
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

The invention pertains to a method for lowering the ablation threshold of a laser-ablated material by having on a surface of the laser-ablated material a structuring which reduces the reflection of a laser beam. The ablation threshold can be further lowered by heating the material as well as by chemically modifying the material or its surface, even slightly. The invention facilitates industrial implementation of machining of a number of various surfaces and materials. The invention also pertains to target materials to be ablated.

Claims

1. A method for lowering the ablation threshold of a laser-ablatable material, characterized in that on a surface, of the material ablatable by cold-work laser, there is a structuring which reduces the reflection of the laser beam.

2. A method according to claim 1, characterized in that the laser apparatus used in the ablation of the material is a cold-work laser, such as a picosecond laser

3. A method according to claim 1, characterized in that the power of the laser apparatus is at least 10 W, advantageously at least 20 W, and preferably at least 50 W.

4. A method according to claim 1, characterized in that the transverse diameter of an individual structure in the structuring is 0.1 μ

m to 1 mm, advantageously 0.3 μ

m to 100 μ

m, and preferably 0.5 μ

m to 1.5 μ

m.

5. A method according to claim 1, characterized in that the transverse diameter of an individual structure is equal to or smaller than the measure of the wavelength of the laser light used in the ablation.

6. A method according to claim 1, characterized in that the diameter in the direction of depth of an individual structure is 0.1 μ

m to 1 mm, advantageously 0.3 μ

m to 100 μ

m, and preferably 0.5 μ

m to 3 μ

m.

7. A method according to claim 6, characterized in that the diameter in the direction of depth of an individual structure is not more than twice the measure of the wavelength of the laser light used in the ablation.

8. A method according to claim 1, characterized in that the laser-ablatable material is heated in connection with the ablation.

9. A method according to claim 8, characterized in that the laser-ablatable material is heated toward the conductivity threshold temperature of the material.

10. A method according to claim 1, characterized in that the material to be ablated, by a cold work laser, is composed of metal, metal alloy, glass, stone, ceramic, synthetic polymer, semi-synthetic polymer, paper, cardboard, natural polymer, composite material, inorganic or organic monomer or oligomer.

11. A method according to claim 1, characterized in that the laser-ablatable material is treated chemically such that its ablation threshold is lowered.

12. A method according to claim 11, characterized in that the material to be ablated is doped with a material which lowers the ablation threshold.

13. A method according to claim 11, characterized in that the surface layer of the material to be ablated is treated chemically or thermally so that the ablation threshold of the material is lowered.

14. A method according to claim 13, characterized in that the surface layer of the material to be ablated is oxidized, nitridized or carburized.

15. A method according to claim 1, characterized in that the material to be ablated is in the form of a lamella or thread.

16. A method according to claim 1, characterized in that the material to be ablated is in the form of a film or tape.

17. A method according to claim 16, characterized in that the thickness of the material to be ablated is 1 μ

m to 5 mm, advantageously 20 μ

m to 1 mm, and preferably 50 μ

m to 200 μ

m.

18. A method according to claim 1, characterized in that the laser ablation is performed in normal atmospheric pressure or in a gaseous atmosphere such as nitrogen, oxygen, carbon dioxide or hydrocarbon.

19. A method according to claim 1, characterized in that the laser ablation is performed in a vacuum in which the pressure is 10⁻

1 to 10<sup>−

12</sup> atm.

20. A method according to claim 1, characterized in that material is ablated by a laser beam so that material is vaporized essentially all the time at a spot which has not yet been significantly ablated.

21. A method according to claim 1, characterized in that the laser beam is directed to the ablatable material through a turbine scanner.

22. A method according to claim 21, characterized in that the scanning width directed to the target is 1 mm to 800 mm, advantageously 100 mm to 400 mm, and preferably 150 mm to 300 mm.

23. A target material ablatable by laser, characterized in that on a surface of the laser-ablatable material by cold-work laser, there is a structuring which reduces the reflection of a laser beam.

24. A target material according to claim 23, characterized in that the transverse diameter of an individual structure in the structuring is 0.1 μ

m to 1 mm, advantageously 0.3 μ

m to 100 μ

m, and preferably 0.5 μ

m to 1.5 μ

m.

25. A target material according to claim 23, characterized in that the transverse diameter of an individual structure is equal to or smaller than the measure of the wavelength of the laser light used in the ablation.

26. A target material according to claim 23, characterized in that the diameter in the direction of depth of an individual structure is 0.1 μ

m to 1 mm, advantageously 0.3 μ

m to 100 μ

m, and preferably 0.5 μ

m to 3 μ

m.

27. A target material according to claim 26, characterized in that the diameter in the direction of depth of an individual structure is not more than twice the measure of the wavelength of the laser light used in the ablation.

28. A target material according to claim 23, characterized in that the material to be ablated is composed of metal, metal alloy, glass, stone, ceramic, synthetic polymer, semi-synthetic, polymer, paper, cardboard, natural polymer, composite material, or inorganic or organic monomer or oligomer.

29. A target material according to claim 23, characterized in that the laser-ablatable material is treated chemically or thermally such that its ablation threshold is lowered.

30. A target material according to claim 29, characterized in that the material to be ablated is doped with a material which lowers the ablation threshold.

31. A target material according to claim 29, characterized in that the surface layer of the material to be ablated is treated chemically such that the ablation threshold of the material is lowered.

32. A target material according to claim 31, characterized in that the surface layer of the material to be ablated is oxidized, nitridized or carburized.

33. A target material according to claim 23, characterized in that the target material is in the form of a lamella.

34. A target material according to claim 23, characterized in that the target material is in the form of a film or tape.

35. A target material according to claim 34, characterized in that the thickness of the target material is 1 μ

m to 5 mm, advantageously 20 μ

m to 1 mm, and preferably 50 μ

m to 200 mm.