Systems and methods for inducing crystallization of thin films using multiple optical paths

• US 7,318,866 B2
• Filed: 01/09/2004
• Issued: 01/15/2008
• Est. Priority Date: 09/16/2003
• 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
• Primary Examiner(s): Kunemund; Robert
• Application Number:
  US10/754,260
• Publication Number:
  US 20050059224A1
• Time in Patent Office: 1,467 Days
• Field of Search: 117/200, 117/201, 117/202, 117/5, 117/6, 117/8, 117/9
• US Class Current: 117/202
• CPC Class Codes: C30B 1/04 Isothermal recrystallisation
• CPC Class Codes: G03F 7/70041 by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
• CPC Class Codes: G03F 7/70725 control
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02595 polycrystalline
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/0268 Shape of mask
• CPC Class Codes: H01L 21/02683 Continuous wave laser beam
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• CPC Class Codes: Y10T 117/10 Apparatus
• CPC Class Codes: Y10T 117/1004 with means for measuring, testing, or sensing
• CPC Class Codes: Y10T 117/1008 with responsive control means

Abstract

The present invention is directed to systems and methods for irradiating regions of a thin film sample(s) with laser beam pulses having different energy beam characteristics that are generated and delivered via different optical paths. Exemplary methods include the steps of generating a plurality of laser beam pulses having energy beam characteristics, directing a generated laser beam pulse onto a first optical path, modulating the energy beam characteristics of the first optical path-directed laser beam pulse, irradiating at least a portion of a first region of the thin film with the first optical path-directed laser beam pulse to induce crystallization of the portion of the first region, directing a generated laser beam pulse onto a second optical path, modulating the energy beam characteristics of the second optical path-directed laser beam pulse, wherein the energy beam characteristics of the second optical path-directed laser beam pulse is different from the energy beam characteristics of the first optical path-directed laser beam pulse, and irradiating at least a portion of a second region of the thin film with the second optical path-directed laser beam pulse to induce crystallization of the portion of the second region. An exemplary system includes a first optical path, a second optical path, a beam steering element for directing laser beam pulses onto the first optical path and the second optical path; and a handling stage for controlling the position of a thin film relative to the laser beam pulses being directed via the first and second optical paths.

Claims

1. A system for processing a thin film, comprising:

a beam steering element for directing laser beam pulses between at least one of a first optical path and a second optical path;

at least one first optical element for modulating energy beam characteristics of laser beam pulses directed onto said first optical path;

at least one second optical element for modulating energy beam characteristics of laser beam pulses directed onto said second optical path, wherein at least one of the first and second optical elements is selected to provide at least one energy beam characteristic of laser beam pulses directed onto said second optical path that is different than an energy beam characteristic of laser beam pulses directed onto said first optical path;

wherein said laser beam pulses directed onto said first optical path are directed to at least a portion of a first region of said thin film, and wherein said laser beam pulses directed onto said second optical path are directed to at least a portion of a second region of said thin film; and

a handling stage for controlling the position of said thin film relative to said laser beam pulses being directed via said first optical path and said second optical path, wherein said delivery of said first optical path-directed laser beam pulses and said second optical path-directed laser beam pulses to said thin film can induce melting and subsequent crystallization of said thin film.

2. The system of claim 1, further comprising a laser beam source for generating laser beam pulses, wherein said laser beam pulses generated by said laser beam source are directed towards said beam steering element.

3. The system of claim 2, wherein said laser beam source consists of at least one of the following:

a continuous wave laser, a solid state laser and an excimer laser.

4. The system of claim 1, further comprising:

a first mask having a first masking pattern;

a second mask having a second masking pattern; and

wherein said first mask is located on said first optical path and said second mask is located on said second optical path.

5. The system of claim 4, wherein said first masking pattern is configured to facilitate crystallization of said portion of said first region of a first preselected grain length or first grain orientation and said second masking pattern is configured to facilitate crystallization of said portion of said second region of a second preselected grain length or second grain orientation.

6. The system of claim 1, further comprising a pulse duration extender that is capable of extending a pulse duration of a laser beam pulse.

7. The system of claim 6, wherein laser beam pulses travel through said pulse duration extender prior to entering said beam steering element.

8. The system of claim 6, wherein laser beam pulses travel through said pulse duration extender after exiting said beam steering element.

9. The system of claim 1, further comprising:

a first mask and a first projection lens;

a second mask and a second projection lens; and

wherein said first mask and said first projection lens are located on said first optical path and said second mask and said second projection lens are located on said second optical path.

10. The system of claim 9, further comprising:

an attenuator and a homogenizing lens element, wherein laser beam pulses travel through said attenuator and said homogenizing lens element prior to entering said beam steering element.

11. The system of claim 9, further comprising:

a first variable-focus field lens;

a second variable-focus field lens; and

wherein said first variable-focus field lens is located on said first optical path and said second variable-focus field lens is located on said second optical path.

12. The system of claim 9, further comprising:

a first attenuator and a first homogenizing lens element;

a second attenuator and a second homogenizing lens element; and

wherein said first attenuator and said first homogenizing lens element are located on said first optical path and said second attenuator and said second homogenizing lens element are located on said second optical path.

13. The system of claim 1, wherein irradiation conditions of said first region and said second region are selected from those suitable for at least one of the following:

sequential laser solidification, excimer laser anneal and uniform grain structure crystallization.

14. The system of claim 13, wherein said irradiation conditions of said first region are suitable for sequential laser solidification and said irradiation conditions of said second regions are suitable for uniform grain structure crystallization.

15. The system of claim 1, wherein said thin film comprises a semiconductor material.

16. The system of claim 15, wherein said semiconductor material comprises silicon, germanium or silicon-germanium.

17. The system of claim 1, wherein said first region of said thin film comprises an integration region of a display system.

18. The system of claim 17, wherein said second region of said thin film comprises a pixel region of said display system.

19. The system of claim 1, wherein said thin film comprises a metallic material.

20. The system of claim 19, wherein said metallic material comprises at least one of the following:

aluminum, copper, nickel, molybdenum, titanium and gold.

21. The system of claim 1, further comprising controls for producing different crystalline structures in the first and second regions, wherein the controls control at least one optical element in at least one of the first and second optical paths and control the position of the thin film relative to the laser beam pulses.

22. A system for processing a plurality of thin films, comprising:

a beam steering element for directing laser beam pulses between at least first and second optical paths;

at least one optical element for modulating energy beam characteristics of laser beam pulses directed onto said first optical path;

at least one optical element for modulating energy beam characteristics of laser beam pulses directed onto said second optical path;

a first handling stage for controlling the position of a thin film relative to said laser beam pulses being directed via said first optical path;

a second handling stage for controlling the position of a thin film relative to said laser beam pulses being directed via said second optical path;

wherein said laser beam pulses directed onto said first optical path are directed to at least a portion of a region of a thin film, and wherein said laser beam pulses directed onto said second optical path are directed to at least a portion of a region of a different thin film; and

wherein said delivery of said first optical path-directed laser beam pulses and said second optical path-directed laser beam pulses to said thin film can induce melting and subsequent crystallization of said thin films.

23. The system of claim 22, wherein at least one optical element for modulating energy beam characteristics of laser beam pulses directed onto said second optical path is selected to provide at least one energy beam characteristic that is different than an energy beam characteristic of laser beam pulses directed onto said first optical path.