Process and mask projection system for laser crystallization processing of semiconductor film regions on a substrate

• US 6,961,117 B2
• Filed: 11/27/2001
• Issued: 11/01/2005
• Est. Priority Date: 11/27/2000
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Im, James S.
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US10/432,485
• Publication Number:
  US 20040061843A1
• Time in Patent Office: 1,435 Days
• Field of Search: 355/53, 355 67- 71, 355/77, 250/492.2, 250/548, 356399-401
• US Class Current: 355/67
• CPC Class Codes: B23K 26/0604 by a combination of beams
• CPC Class Codes: B23K 26/0608 in the same heat affected zone [HAZ] B23K26/0613, B23K26/0619 take precedence
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: G03B 27/42 for automatic sequential copying of the same original G03B27/34, G03B27/53 take precedence
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• CPC Class Codes: H01L 21/76894 using a laser, e.g. laser cutting, laser direct writing, laser repair

Abstract

A process and system for processing a silicon thin film on a sample are provided. In particular, an irradiation beam generator is controlled to emit irradiation beam pulses at a predetermined repetition rate. These irradiation beam pulses are then separated into a first set of beam pulses and a second set of beam pulses. The first set of beam pulses are caused to irradiate through a mask to produce a plurality of beamlets. The second set of beam pulses and the beamlets are caused to impinge and irradiate at least one section of the silicon thin film. When the second set of beam pulses and the beamlets simultaneously irradiate the section of the silicon thin film, this combination of the beamlets and second set of beam pulses provides a combined intensity which is sufficient to melt the section of the silicon thin film throughout an entire thickness of the section.

Claims

1. A process for processing a silicon thin film on a sample, comprising the steps of:

(a) controlling an irradiation beam generator to emit irradiation beam pulses at a predetermined repetition rate;

(b) separating file irradiation beam pulses into a first set of separated beam pulses and a second set of separated beam pulses;

(c) forwarding the first set of separated beam pulses to irradiate and pass at least portions thereof through a mask to produce a plurality of beamlets; and

(d) providing the second set of separated beam pulses and the beamlets to impinge and irradiate at least one section of the silicon thin film, wherein, when the second set of separated beam pulses and the beamlets simultaneously irradiate the at least one section of the silicon thin film, the second set of the separated beam pulses and the beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film throughout an entire thickness of the section.

2. The process according to claim 1, wherein the first set of separated beam pulses has a corresponding intensity which is lower than an intensity required to damage or degrade the mask.

3. The process according to claim 1, wherein step (c) includes the substep of preventing the second set of separated beam pulses from being forwarded to the mask.

4. The process according to claim 3, wherein the preventing substep is performed by diverting the second set of separated beam pulses away from the mask prior to the second set of separated beam pulses reaching the mask.

5. The process according to claim 1, wherein the second set of separated beam pulses has a corresponding intensity which is lower than an intensity required to melt the at least one section of the silicon thin film throughout the entire thickness thereof.

6. The process according to claim 1, wherein, during step (d), the at least one irradiated and melted section of the silicon thin film is allowed to re-solidify and crystallize.

7. The process to claim 6, further comprising the step of:

(e) after step (d) and after the section of the silicon thin film re-solidifies and crystallizes, translating the sample so that the beamlets and the second set of separated beam pulses impinge a further section of the silicon thin film, wherein the further section at least partially overlaps the section that was allowed to re-solidify and crystallize.

8. The process according to claim 7, further comprising the step of:

(f) after step (d) and before step (e), microtranslating the sample so that the beamlets and the second set of separated beam pulses impinge at least one previously irradiated, fully melted, re-solidified and crystallized portion of the section of the silicon thin film.

9. The process to claim 8, wherein the beamlets and the second set of separated beam pulses irradiate and fully melt the section of the silicon thin film from a microtranslated location of impingement on the sample.

10. The process according to claim 8, wherein the mask has a dot-like pattern such that dot portions of the pattern are oblique regions of the mask which prevent certain portions of the first set of separated beam pulses to irradiate there through.

11. The process according to claim 8, wherein the mask has a line pattern such that line portions of the pattern are oblique regions of the mask which prevent certain portions of the first set of separated beam pulses to irradiate there through.

12. The process according to claim 7, wherein the mask has a transparent pattern such that transparent portions of the pattern do not include oblique regions therein, the oblique regions capable of preventing certain portions of the first set of separated beam pulses to irradiate there through.

13. A process for processing a silicon thin film on a sample, comprising the steps of:

(a) controlling an irradiation beam generator arrangement to provide first and second sets of irradiation beam pulses at a predetermined repetition rate;

(b) forwarding the first set of beam pulses to irradiate and pass at least a portion thereof through a mask to produce a plurality of beamlets; and

(c) providing the second set of beam pulses and the beamlets to impinge and irradiate at least one section of the silicon thin film, wherein, when the second set of beam pulses and the beamlets simultaneously irradiate the at least one section of the silicon thin film, the second set of beam pulses and the beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film throughout an entire thickness of the section.

14. The process according to claim 13, wherein a step (a) includes the substeps of:

i. emitting irradiation beam pulses at a predetermined repetition rate, and

ii. separating the irradiation beam pulses into the first set of beam pulses and the second set of beam pulses.

15. The process according to claim 14, wherein substep (ii) is performed prior to the irradiation beam pulses reaching the mask.

16. The process according to claim 13, wherein the first set of beam pulses has a corresponding intensity which is lower than an intensity required to damage or degrade the mask.

17. The process according to claim 13, wherein step (b) includes the substep of preventing the second set of beam pulses from being forwarded to the mask.

18. The process according to claim 16, wherein th preventing substep is performed by diverting the second set of beam pulse away from the mask prior to the second act of beam pulses reaching the mask.

19. The process according to claim 13, wherein the second act of beam pulses has a corresponding intensity which is lower than an intensity required to melt the at least one section of the silicon thin film throughout the entire thickness thereof.

20. The process according to claim 13, wherein, during step (c), the at least one irradiated and melted section of the silicon thin film is allowed to re-solidify and crystallize.

21. The process according to claim 20, further comprising the step of:

(d) after step (c) and after the section of the silicon thin film re-solidifies and crystallizes, translating the sample so that the beamlets and the second set of beams pulses impinge a further section of the silicon thin film, wherein the further section at least partially overlaps the section that was allowed to re-solidify and crystallize.

22. The process according to claim 21, further comprising the step of

(e) after step (c) and before step (d), microtranslating the sample so that the beamlets and the second act of beam, pulses impinge at least one previously irradiated, fully melted, re-solidified and crystallized portion of the section of the silicon thin film.

23. The process according to claim 22, wherein the beamlets and the second set of beams pulses irradiate and fully melt the section of the silicon thin film from a microtranslated location of impingement on the sample.

24. The process according to claim 22, wherein the mask has a dot-like pattern such that dot portions of the pattern oblique regions of the mask which prevent certain portions of the first set of beam pulses to irradiate there through.

25. The process according to claim 22, wherein the mask has a line pattern such that line portions of the pattern are oblique regions of the mask which prevent certain portions of the fist set of beam pulses to irradiate there through.

26. The process according to claim 21, wherein the mask has a transparent pattern such that transparent portions of the pattern do not include oblique region therein, the oblique regions capable of preventing certain portions of the first set of beam pulses to irradiate there through.

27. A system for processing a silicon thin film on a sample, comprising:

a memory storing a computer program; and

processing arrangement executing the computer program to perform the following step;

(a) controlling an irradiation beam generator to emit irradiation beam pulses at a predetermined repetition rate,

(b) causing the irradiation beam pulses to be separated into a first set of separated beam pulses and a second set of separated beam pulses,

(c) forwarding the first set of separated beam pulses to irradiate and pass at least portions thereof through a mask to produce a plurality of beamlets, and

(d) causing the second set of separated beam pulses and the beamlets to impinge and irradiate at least one section of the silicon thin film,

wherein, when the second set of separated beam pulses and the beamlets both simultaneously irradiate the at least one section of the silicon thin film, the second set of separated beam pulses and beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film throughout an entire thickness of the section.

28. The system according to claim 27, further comprising a beam splitter arranged in a vicinity of the processing arrangement, wherein the processing arrangement causes the irradiation beam pulses to be forwarded to the beam splitter which separates the irradiation beam pulses into the first set of separated beam pulses and the second set of separated beam pulses.

29. The system according to claim 28, wherein the beam splitter is located upstream in a path of the irradiation beam pulses from the mask.

30. The system according to claim 27, wherein the first set of separated beam pulses has a corresponding intensity which is lower than an intensity required to damage or degrade the mask.

31. The system according to claim 27, wherein the processing arrangement executes the computer program to prevent the second set of separated beam pulses from being forwarded to the mask.

32. The system according to claim 31, wherein the second set of separated beam pulses from being forwarded to the mask by diverting the second set of separated beam pulses away from the mask prior to the second set of separated beam pulses reaching the mask.

33. The system according to claim 27, wherein the second set of separated beam pulses has corresponding intensity which is lower than an intensity required to melt the at least one section of the silicon thin film throughout the entire thickness thereof.

34. The system according to claim 27, wherein, when at least one section of the silicon thin film is irradiated, the at least one irradiated and melted section of the silicon thin film is allowed to re-solidify and crystallize.

35. The system according to claim 34, wherein the processing arrangement executes the computer program to perform the following further step:

(e) after substep (d) and after the section of the silicon thin film re-solidifies and crystallizes, causing a translation of the sample so that the beamlets and the second set of separated beam pulses impinge a further section of the silicon thin film, wherein the further section at least partially overlaps the section that was allowed to re-solidify and crystallize.

36. The system according to claim 35, wherein the processing arrangement executes the computer program to perform the following further step:

(f) after substep (d) and before substep (e), causing a microtranslation of the sample so that the beamlets and the second set of separated beam pulses impinge at least one previously irradiated, fully melted, re-solidified and crystallized portion of the section of the silicon thin film.

37. The system according to claim 36, wherein the beamlets and the second set of separated beam pulses irradiate and fully melt the section of the silicon thin film from a microtranslated location of impingement of the sample.

38. The system according to claim 36, wherein the mask has a dot-like pattern such that dot portions of the pattern are oblique regions of the mask which prevent certain portions of the first set of separated beam pulses to irradiate there through.

39. The system according to claim 36, wherein the mask has a line pattern such that line portions of the pattern are oblique regions of the mask which prevent certain portions of the first set of separated beam pulses to irradiate there through.

40. The system according to claim 35, wherein the mask has a transparent pattern such that transparent portions of the pattern do not include oblique regions therein, the oblique regions capable of preventing certain portions the first set of separated beam pulses to irradiate there through.

41. A system for processing a silicon thin film on a sample, comprising:

a memory storing a computer program; and

a processing arrangement executing the computer program to perform the following steps;

(a) controlling an irradiation beam generator arrangement to provide first and second sets of irradiation beam pulses at a predetermined repetition rate,

(b) causing the first set of beam pulses to be irradiated and pass at least a portion thereof through a mask to produce a plurality of beamlets, and

(c) causing the second set of beam pulses and the beamlets to impinge and irradiate at least one section of the silicon thin film,

wherein, when the second set of beam pulses and the beamlets simultaneously irradiate the at least one section of the silicon thin film, the second set of beam pulses and the beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film, throughout an entire thickness of the section.

42. The system according to claim 41, wherein the processing arrangement causes the irradiation beam generator arrangement to emit irradiation beam pulses at a predetermined repetition rate.

43. The system according to claim 41, further comprising a beam splitter arranged in a vicinity of the processing arrangement, wherein the processing arrangement causes the irradiation beam pulses to be forwarded to the beam splitter which separates the irradiation beam pulses into the first set of beam pulses and the second set of beam pulses.

44. The system according to claim 41, wherein the beam splitter is located upstream in a path of the irradiation beam pulses from the mask.

45. The system according to claim 43, wherein the beam splitter separates the irradiation beam pulses into the first set of beam pulses and the second set of beam pulses prior to the irradiation beam pulses reaching the mask.

46. The system according to claim 41, wherein the first set of beam pulses has a corresponding intensity which is lower than as intensity required to damage or degrade to the mask.

47. The system according to claim 41, wherein the processing arrangement executes the computer program to prevent the second set of beam pulses from being forwarded to the mask.

48. The system according to claim 47, wherein the second set of beam pulses from being forwarded to the mask by diverting the second set of beam away from the mask prior to the second set of beam pulses reaching the mask.

49. The system according to claim 41, wherein the second set of beam pulses has a corresponding intensity which is lower than an intensity required to melt the at least one section of the silicon thin film throughout the entire thickness thereof.

50. The system according to claim 41, wherein, when at least one section of the silicon thin film is irradiated, the at least one irradiated and melted section of the silicon thin film is allowed to re-solidify and crystallize.

51. The system according to claim 50, wherein the processing arrangement executes the computer program to perform the following further step:

(d) after substep (c) and after the section of the silicon thin film re-solidifies and crystallizes, causing a translation of the sample so that the beamlets and the second set of beam pulses impinge a further section of the silicon thin film, wherein the further section at least partially overlaps the section that was allowed to re-solidify and crystallize.

52. The system according to claim 51, wherein the processing arrangement executes the computer program to perform the following further step:

(e) after substep (c) and before substep (d), causing a microtranslation of the sample so that the beamlets and the second set of beam pulses impinge at least one previously irradiated, fully melted, re-solidified and crystallized portion of the section of the silicon thin film.

53. The system according to claim 52, wherein the beamlets and the second set of beam pulses irradiate and fully melt the section of the silicon thin film from a microtranslated location of the sample.

54. The system according to claim 52, wherein the mask has a dot-like pattern such that dot portions of the pattern a oblique regions of the mask which prevent certain portions of the first set of beam pulses to irradiate there through.

55. The system according to claim 52, wherein the mask has a line pattern such that line portions of the pattern are oblique regions of the mask which prevent certain portions of the first set of beam pulse to irradiate there through.

56. The system according to claim 51, wherein the mask has a transparent pattern such that transparent portions of the pattern do not include oblique regions therein, the oblique regions capable of preventing certain portions of the first set of beam pulses to irradiate there through.

57. A system for processing a silicon thin film on a sample, comprising:

a processing arrangement programmed to control an irradiation beam generator to emit irradiation beam pulses at a predetermined repetition rate;

a beam separation arrangement which, when receiving the irradiation beam pulses, separates the irradiation beam into a first set of beam pulses and a second set of beam pulses; and

a mask configured to receive thereon the first set of beam pulses, and produce a plurality of beamlets.

wherein tho processing arrangement is further programmed to position the sample with respect to a direction of the irradiation beam pulses such that the second set of beam pulses and the beamlets impinge an irradiate at least one section of the thin film, and

wherein, when the second set of beam pulses and the beamlets both simultaneously irradiate the at least one section of the thin film, the second set of beam pulses and beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film throughout an entire thickness of the section.

58. An arrangement for processing a silicon thin film on a sample, comprising:

a processing arrangement programmed to control an irradiation beam generator to emit irradiation beam pulses at a predetermined repetition rate;

a beam separation arrangement which, when receiving the irradiation beam pulses, separates the irradiation beam into at least one first pulse and at least one second pulse; and

a mask configured to receive thereon the at least one first pulse, and produce a plurality of beamlets,

wherein the processing arrangement is further programmed to position the sample with respect to a direction of the irradiation beam pulses such that the at least one second pulse and the beamlets impinge and irradiate at least one section of the thin film, and

wherein, when the at least one second pulse and the beamlets both simultaneously irradiate the at least one section of the thin film, the at least one second pulse and beamlets provide a combined intensity which is sufficient to melt the at least

(b) causing the irradiation beam pulses to be separated into a first set of separated beam pulses and a second set of separated beam pulses,

(c) forwarding the first set of separated beam pulses to irradiate and pass at least portions thereof through a mask to produce a plurality of beamlets, and

(d) causing the second set of separated beam pulses and the beamlets to impinge and irradiate at least one section of the silicon thin film,

wherein, when the second set of separated beam pulses and the beamlets both simultaneously irradiate the at least on section of the silicon thin film, the second set of separated beam pulses and beamlets provide a combined intensity which is sufficient to melt the at least one irradiated section of the silicon thin film throughout an entire thickness of the section.