Laser processing of alumina or metals on or embedded therein

• US 20020063361A1
• Filed: 09/19/2001
• Published: 05/30/2002
• Est. Priority Date: 09/20/2000
• Status: Abandoned Application

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Inventors: Fahey, Kevin P.
• Application Number:
  US09/957,633
• Publication Number:
  US 20020063361A1
• Time in Patent Office: Days
• US Class Current: 264/400
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less

Abstract

UV laser output (190) is employed to sever a conductive shunt (106) formed across conductive components, such as read pads, of a magnetic head (10) of a slider (14) without damaging underlayers sensitive to UV laser light. An exemplary conductive shunt (106) is preferably fabricated from gold other appropriate metal(s) and forms a closed circuit with the magnetic head sensor (20) to protect it from damage from electrostatic discharge during polishing and other magnetic head processing steps. The conductive shunt (106) may be on or embedded in an alumina layer(44), permitting shunting at different workpiece layers and permitting the shunting to be present through more subsequent process steps and removed after singulation or during final assembly.

Claims

1. A method for processing a magneto-resistive head having a conductive shunt between two metallic read pads in communication with a magnetic sensor of a thin film magnetic head such that the conductive shunt is in electrical contact with the metallic pads to create a short circuit that protects the magneto-resistive head from electrostatic discharge, comprising:

generating and directing UV laser system output having a wavelength shorter than 350 nm toward the conductive shunt; and

severing the conductive shunt with the UV laser system output to eliminate the short circuit between the metallic pads.

2. The method of claim 1 in which the conductive shunt is formed on a surface of a passivation layer and has an exposed surface.

3. The method of claim 2 in which the passivation layer comprises deposited alumina.

4. The method of claim 1 in which the conductive shunt is buried within a passivation layer.

5. The method of claim 4 in which the passivation layer comprises deposited alumina.

6. The method of claim 5 in which magneto-resistive head comprises at least one head component that is positioned beneath the conductive shunt and is susceptible to damage from ultraviolet laser system output.

7. The method of claim 3 in which the continuous contact pad member comprises a height of greater than 5 μ

m.

8. The method of claim 7 in which the continuous contact pad member comprises a height of greater than about 10 μ

m.

9. The method of claim 3 in which the conductive shunt comprises gold.

10. The method of claim 5 in which the conductive shunt comprises gold.

11. The method of claim 7 in which the conductive shunt comprises gold.

12. The method of claim 1 in which the UV laser system output comprises a wavelength shorter than about 266 nm.

13. The method of claim 3 in which the UV laser system output comprises a wavelength shorter than or equal to about 266 nm.

14. The method of claim 5 in which the UV laser system output comprises a wavelength shorter than or equal to about 266 nm.

15. The method of claim 7 in which the UV laser system output comprises a wavelength shorter than or equal to about 266 nm.

16. The method of claim 11 in which the UV laser system output comprises a wavelength shorter than or equal to about 266 nm.

17. The method of claim 13 in which a solid-state laser system generates the UV laser system output.

18. The method of claim 14 in which a solid-state laser system generates the UV laser system output.

19. The method of claim 15 in which a solid-state laser system generates the UV laser system output.

20. The method of claim 16 in which a solid-state laser system generates the UV laser system output.

21. The method of claim 20 in which the UV laser system output comprises a spot size between about 5-30 μ

m, a pulse energy of greater than about 20 μ

J, and a repetition rate of greater than about 5 kHz.

22. The method of claim 17 in which the UV laser system output comprises at least two laser pulses.

23. The method of claim 18 in which the UV laser system output comprises at least two laser pulses.

24. The method of claim 20 in which the UV laser system output comprises at least two laser pulses.

25. The method of claim 1 in which the UV laser system output is generated after the magneto-resistive head is polished.

26. The method of claim 20 in which the UV laser system output is generated after the magneto-resistive head is polished.

27. The method of claim 1 in which the UV laser system output is generated after the magneto-resistive head is assembled into a head stack assembly.

28. The method of claim 20 in which the UV laser system output is generated after the magneto-resistive head is assembled into a head stack assembly.

29. The method of claim 1 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

30. The method of claim 3 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

31. The method of claim 5 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

32. The method of claim 20 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

33. The method of claim 13 in which an excimer laser system generates the UV laser system output.

34. The method of claim 14 in which an excimer laser system generates the UV laser system output.

35. The method of claim 3 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

36. The method of claim 5 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

37. The method of claim 20 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

38. The method of claim 17 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

39. The method of claim 18 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

40. The method of claim 19 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

41. The method of claim 21 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

42. A method for processing a thin film magnetic head having a conductive shunt between two electrically conductive components such that the conductive shunt is in electrical contact with the electrically conductive components to create a short circuit that protects the magnetic head from electrical damage, comprising:

generating and directing UV laser system output having a wavelength shorter than 350 nm toward a conductive shunt buried beneath a deposited alumina layer and positioned above another head component susceptible to damage from ultraviolet laser system output; and

severing the conductive shunt with the UV laser system output to eliminate the short circuit between the electrically conductive components.

43. The method of claim 42 in which the UV laser system output comprises a wavelength shorter than or equal to about 266 nm.

44. The method of claim 43 in which the conductive shunt comprises gold.

45. The method of claim 43 in which a solid-state laser system generates the UV laser system output.

46. The method of claim 42 in which an excimer laser system generates the UV laser system output.

47. The method of claim 43 in which the UV laser system output comprises a spot size between about 5-30 μ

m, a pulse energy of greater than about 20 μ

J, and a repetition rate of greater than about 5 kHz.

48. The method of claim 43 in which the UV laser system output comprises at least two laser pulses.

49. The method of claim 47 in which the UV laser system output comprises at least two laser pulses.

50. The method of claim 42 in which the UV laser system output is generated after the magneto-resistive head is polished.

51. The method of claim 43 in which the UV laser system output is generated after the magneto-resistive head is polished.

52. The method of claim 49 in which the UV laser system output is generated after the magneto-resistive head is polished.

53. The method of claim 42 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

54. The method of claim 43 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

55. The method of claim 47 in which the conductive shunt is positioned such that it is distant from and nonoverlapping with a dicing line.

56. The method of claim 42 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

57. The method of claim 43 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

58. The method of claim 47 further comprising:

testing the magnetic head;

reconnecting the shunt;

further processing the slider; and

re-severing the shunt.

59. The method of claim 42 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

60. The method of claim 43 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

61. The method of claim 47 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.

62. The method of claim 58 in which the laser system output has a clipped Gaussian irradiance profile or an imaged shaped Gaussian irradiance profile.