Apparatus and method for exposing a substrate to UV radiation using asymmetric reflectors

• US 7,692,171 B2
• Filed: 03/15/2007
• Issued: 04/06/2010
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Hendrickson, Scott A., Baluja, Sanjeev, Kaszuba, Andrzei, Nowak, Thomas, Rocha-Alvarez, Juan Carlos, Cho, Tom K., M'Saad, Hichem, Ho, Dustin W.
• Primary Examiner(s): Vanore; David A
• Application Number:
  US11/686,900
• Publication Number:
  US 20080067425A1
• Time in Patent Office: 1,118 Days
• Field of Search: None
• US Class Current: 250/504.00R
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G21K 1/062 Devices having a multilayer structure
• CPC Class Codes: G21K 2201/061 characterised by a multilayer structure
• CPC Class Codes: G21K 2201/064 having a curved surface
• CPC Class Codes: G21K 2201/067 Construction details
• CPC Class Codes: H01L 21/67115 mainly by radiation

Abstract

Embodiments of the invention relate generally to an ultraviolet (UV) cure chamber for curing a dielectric material disposed on a substrate and to methods of curing dielectric materials using UV radiation. A substrate processing tool according to one embodiment comprises a body defining a substrate processing region; a substrate support adapted to support a substrate within the substrate processing region; an ultraviolet radiation lamp spaced apart from the substrate support, the lamp configured to transmit ultraviolet radiation to a substrate positioned on the substrate support; and a motor operatively coupled to rotate at least one of the ultraviolet radiation lamp or substrate support at least 180 degrees relative to each other. The substrate processing tool may further comprise one or more reflectors adapted to generate a flood pattern of ultraviolet radiation over the substrate that has complementary high and low intensity areas which combine to generate a substantially uniform irradiance pattern if rotated. Other embodiments are also disclosed.

Claims

1. A substrate processing tool comprising:

a body defining a substrate processing region;

a substrate support adapted to support a substrate within the substrate processing region; and

a first UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the first UV lamp comprising a first UV radiation source and a first reflector partially surrounding the first UV radiation source, the first reflector having opposing inner and outer reflective panels, the inner reflective panel having a first reflective surface and the outer reflective panel having a second reflective surface that is asymmetric to the first reflective surface.

2. A substrate processing tool comprising:

a body defining a substrate processing region;

a substrate support adapted to support a substrate within the substrate processing region;

a first UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the first UV lamp comprising a first UV radiation source and a first reflector partially surrounding the first UV radiation source, the first reflector having opposing inner and outer reflective panels, the inner reflective panel having a first reflective surface and the outer reflective panel having a second reflective surface that is asymmetric to the first reflective surface; and

second UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the second UV lamp comprising a second UV radiation source and a second reflector partially surrounding the second UV radiation source, the second reflector opposing inner and outer reflective panels, the inner reflective panel having a third reflective surface and the outer reflective panel having a fourth reflective surface that is asymmetric to the third reflective surface.

3. The substrate processing tool of claim 2 wherein the first reflector is configured to transmit UV radiation to a first portion of the substrate and the second reflector is configured to transmit the UV radiation to a second portion of the substrate generally different from the first portion.

4. The substrate processing tool of claim 3 wherein each of the first and second UV lamps are mounted at an angle of between 2-25 degrees relative to vertical and the first, second, third and fourth reflective surfaces are adapted to generate an irradiance pattern that compensates for the angle.

5. The substrate processing tool of claim 2 further comprising a window separating the substrate processing region from the first and second UV lamps, wherein the window is positioned such that UV radiation is transmitted through the window prior to reaching the substrate.

6. The substrate processing tool of claim 2 wherein the first UV lamp is mounted at an angle of between 2-25 degrees relative to vertical and the first and second asymmetric reflective surfaces are adapted to generate an irradiance pattern that compensates for the angle.

7. A substrate processing tool comprising:

a body defining a substrate processing region;

a substrate support adapted to support a substrate within the substrate processing region;

a first UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the first UV lamp comprising a first elongated UV radiation source and a first reflector partially surrounding the first elongated UV radiation source, the first reflector having opposing inner and outer reflective panels, the inner reflective panel having a first reflective surface and the outer reflective panel having a second reflective surface that is asymmetric to the first reflective surface; and

a second UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the second UV lamp comprising a second elongated UV radiation source and a second reflector partially surrounding the second elongated UV radiation source, the second reflector opposing inner and outer reflective panels, the inner reflective panel having a third reflective surface and the outer reflective panel having a fourth reflective surface that is asymmetric to the third reflective surface.

8. The substrate processing tool of claim 7 wherein the first and second reflective surfaces concentrate radiation on approximately one half of the substrate and the third and fourth reflective surfaces concentrate radiation on approximately the opposing half of the substrate.

9. The substrate processing tool of claim 8 wherein the second and fourth reflective surfaces combine to concentrate radiation in an area that covers the center of the substrate, the first reflective surface is configured to direct a high irradiance spot of radiation at a first outer peripheral portion of the substrate and the third reflective surface is configured to direct a high irradiance spot of radiation at a second outer peripheral portion of the substrate opposite the first outer peripheral portion.

10. The substrate processing tool of claim 7 wherein the second reflective surface is symmetric to the fourth reflective surface.

11. The substrate processing tool of claim 10 wherein the first reflective surface is symmetric to the third reflective surface.

12. The substrate processing tool of claim 11 wherein each of the first and second elongated UV radiation sources comprises a single elongated UV bulb.

13. The substrate processing tool of claim 7 further comprising a third reflector positioned between the first and second reflectors and the substrate support, wherein the third reflector is adapted to reduce UV radiation loss outside the substrate.

14. The substrate processing tool of claim 13 wherein each of the first and second UV lamp generate substantially rectangular flood patterns of UV radiation and the third reflector alters the rectangular flood patterns to create a substantially circular flood pattern.

15. The substrate processing tool of claim 13 wherein the first, second and third reflectors are adapted to generate an irradiance pattern having areas of low and high intensity that compensate for each other to form a substantially uniform irradiance pattern when rotated.

16. The substrate processing tool of claim 15 wherein the third reflector comprises an upper portion and a lower portion each of which includes (i) opposing longitudinal surfaces that meet at a vertex traversing a length of the longitudinal surfaces;

and (ii) opposing transverse surfaces extending between ends of the longitudinal surfaces.

17. A substrate processing system comprising:

a body defining first and second processing regions that are separate and adjacent to one another;

a first substrate support adapted to support a first substrate within the first processing region and a second substrate support adapted to support a second substrate within the second processing region;

a first UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the first UV lamp comprising a first UV radiation source and a first reflector partially surrounding the first UV radiation source, the first reflector having opposing inner and outer reflective panels, the inner reflective panel having a first reflective surface and the outer reflective panel having a second reflective surface that is asymmetric to the first reflective surface;

a second UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the second UV lamp comprising a second UV radiation source and a second reflector partially surrounding the second UV radiation source, the second reflector opposing inner and outer reflective panels, the inner reflective panel having a third reflective surface and the outer reflective panel having a fourth reflective surface that is asymmetric to the third reflective surface;

a third UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the first UV lamp comprising a third UV radiation source and a third reflector partially surrounding the third UV radiation source, the third reflector having opposing inner and outer reflective panels, the inner reflective panel having a fifth reflective surface and the outer reflective panel having a sixth reflective surface that is asymmetric to the fifth reflective surface; and

a fourth UV lamp spaced apart from the substrate support and configured to transmit UV radiation to a substrate positioned on the substrate support, the fourth UV lamp comprising a fourth UV radiation source and a fourth reflector partially surrounding the fourth UV radiation source, the fourth reflector opposing inner and outer reflective panels, the inner reflective panel having a seventh reflective surface and the outer reflective panel having an eighth reflective surface that is asymmetric to the seventh reflective surface.

18. The substrate processing tool of claim 17 wherein the first and second reflective surfaces concentrate radiation on one half of the first substrate and the third and fourth reflective surfaces concentrate radiation on the opposing half of the first substrate and wherein the fifth and sixth reflective surfaces concentrate radiation on one half of the second substrate and the seventh and eighth reflective surfaces concentrate radiation on the opposing half of the second substrate.

19. The substrate processing system of claim 18 wherein the each of the first and second UV radiation lamp modules comprises an elongated source and a primary reflector adapted to reflect ultraviolet radiation from the elongated source towards its respective substrate support.

20. The substrate processing system of claim 19 further comprising a lid coupled to a top of the body to cover the first and second processing regions, wherein the lid includes first and second UV radiation transparent windows aligned respectively above the first and second process regions, wherein the first window is position between the first and second UV lamps and the first substrate support and the second window is positioned between the third and fourth UV lamps and the second substrate support.

21. A method of curing a layer of dielectric material formed over a substrate, the method comprising:

placing the substrate having the dielectric material formed thereon on a substrate support in a substrate processing chamber; and

exposing the substrate to UV radiation by (i) generating the radiation with first and second UV sources, (ii) redirecting UV radiation generated by the first UV source with first and second reflective surfaces that are asymmetric to each other and combine to concentrate the UV radiation on a first half of the substrate, and (iii) redirecting UV radiation generated by the second UV source with third and fourth reflectors that are asymmetric to each other and combine to concentrate the UV radiation on a second half of the substrate opposite the first half.

22. The method of claim 21 wherein the second and fourth reflective surfaces combine to concentrate radiation in an area that covers the center of the substrate.

23. The method of claim 22 wherein the first reflective surface concentrates radiation in a first outer peripheral portion of the substrate and the third reflective surface concentrates radiation in a second outer peripheral portion of the substrate opposite the first outer peripheral portion.

24. An apparatus for generating ultraviolet radiation, the apparatus comprising:

a resonant cavity;

an elongated bulb positioned within the resonant cavity;

a reflector partially surrounding the elongated bulb and mounted longitudinally within the resonant cavity in a spaced relationship to the bulb, the reflector having opposing inner and outer reflective panels, the inner reflective panel having a first reflective surface and the outer reflective panel having a second reflective surface that is asymmetric to the first reflective surface.

25. The apparatus of claim 24 further comprising a microwave generator operatively coupled to the resonant cavity for energizing the elongated bulb to emit ultraviolet radiation.

26. A method of curing a layer of dielectric material formed over a substrate, the method comprising:

placing the substrate having the dielectric material formed thereon on a substrate support in a substrate processing chamber; and

exposing the substrate to UV radiation by generating the radiation with an elongated UV source and redirecting the UV radiation generated by the UV source with first and second opposing reflective surfaces that partially surround the radiation source and are asymmetric to each other.