Exposure device including an electrically aligned electronic mask for micropatterning

• US 5,229,872 A
• Filed: 01/21/1992
• Issued: 07/20/1993
• Est. Priority Date: 01/21/1992
• Status: Expired due to Term

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Mumola, Peter B.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): TRICE, RONALD
• Application Number:
  US07/822,794
• Time in Patent Office: 546 Days
• Field of Search: 359/40, 359/42, 359/48, 148/DIG. 102, 148/DIG. 104, 437/80, 437/924, 355/20, 355/53, 355/85, 355/86, 355/87, 430/22
• US Class Current: 349/2
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices

Abstract

An apparatus 10 for micropatterning a photoresist coated surface 12 of a semiconductor wafer 14 includes a computer 50 for controlling an image on a screen 29 of a cathode ray tube (CRT) 30. The CRT screen 29 is optically connected to a liquid crystal light valve (LCLV) 26 by a fiber optic faceplate 28. This connection is such that the computer controlled image on the CRT screen 29 is reproduced on the face 27 of the LCLV 26 as a reflective pattern of this image. An argon-ion laser 16 provides a polarized monochromatic light beam 18 that is reflected from the face 27 of the LCLV 26. This reflected beam 32 is convergently focused by a lens system 36 onto a projected area 37 of the photoresist coated wafer surface 12, thereby exposing the photoresist with an image of the LCLV reflective pattern. A helium-neon laser 38 provides a polarized monochromatic light beam 44 that is convergently focused onto the same projected area 37 of the wafer surface 12. However, the wavelength of the helium-neon provided light beam 44 is such that there is no exposure to the photoresist coated wafer surface 12. The helium-neon light beam is reflected from the projected area 37 of the wafer surface 12 and directed toward an image plane 49 of a charge coupled device (CCD) camera 48. The CCD camera 48 captures an image of the projected area 37 of the wafer surface 12 and a computer 50 digitizes this image. The computer 50 determines the position of the wafer 14 with respect to the projected reflective pattern image, and updates the image on the CRT screen 29 if the projected reflective pattern image is not properly aligned onto the wafer surface 12. Thus, the entire surface 12 of the wafer 14 may be micropatterned by moving the wafer 14 and updating the CRT screen 29 image in accordance with this movement.

Claims

1. An apparatus for micropatterning a surface, said surface having a property that is sensitive to irradiation, said apparatus comprising:

means for electronically generating a reflective pattern;

means for irradiating said irradiation sensitive surface with a radiated image of said reflective pattern; and

means for determining the position of said irradiation sensitive surface on which said radiated reflective pattern image is incident, such that said radiated reflective pattern image is properly aligned with said irradiation sensitive surface, and such that when the position of said irradiation sensitive surface moves with respect to said radiated reflective pattern image, said generated reflective pattern changes in accordance with said movement.

2. An apparatus as described in claim 1, wherein said means for generating a reflective pattern comprises:

a cathode ray tube (CRT) for displaying a CRT displayed image;

a liquid crystal light valve (LCLV) for forming a reflective pattern of said CRT displayed image;

a fiber optic faceplate for optically connecting said CRT to said LCLV; and

a computer, electrically connected to said CRT, for controlling said CRT displayed image.

3. An apparatus as described in claim 2, wherein said computer controls said CRT displayed image on a screen of said CRT, wherein said CRT displayed image is optically transferred by said fiber optic faceplate from said CRT screen to said LCLV, and wherein said reflective pattern of said CRT displayed image is formed on a face of said LCLV.

4. An apparatus as described in claim 3, wherein said reflective pattern of said CRT displayed image is used as a lithographic mask pattern for exposing a photoresist coated surface of a semiconductor wafer.

5. An apparatus as described in claim 1, wherein said means for irradiating comprises a means for irradiating with monochromatic light.

6. An apparatus as described in claim 5, wherein said means for irradiating with monochromatic light comprises:

a source for providing a polarized monochromatic light beam;

a collimator for collimating said polarized monochromatic light beam;

a liquid crystal light value (LCLV) for forming said reflective pattern from which said collimated and polarized monochromatic light beam is reflected;

a plurality of polarizing beam splitters for directing said collimated and polarized monochromatic light beam;

a quarter wave plate (QWP) for changing the polarization of said collimated and polarized monochromatic light beam; and

a lens system for focusing said collimated and polarized monochromatic light beam.

7. An apparatus as described in claim 6, wherein said reflected, collimated, and polarized monochromatic light beam is convergently focused onto said irradiation sensitive surface by said lens system.

8. An apparatus as described in claim 7, wherein an image of said reflective pattern is irradiated onto said irradiation sensitive surface by said convergently focused polarized monochromatic light beam.

9. An apparatus as described in claim 8, wherein said irradiation sensitive surface is a photoresist coated surface of a semiconductor wafer, and wherein said reflective pattern image is exposed onto said photoresist coated surface by said convergently focused polarized monochromatic light beam.

10. An apparatus as described in claim 6, wherein said source for providing a polarized monochromatic light beam is an argon-ion laser.

11. An apparatus as described in claim 1, wherein said means for determining the position of said irradiation sensitive surface comprises:

a source for providing a polarized monochromatic light beam;

a collimator for collimating said polarized monochromatic light beam;

a plurality of beam splitters for directing said collimated and polarized monochromatic light beam;

a lens system for providing a converging focus to said collimated and polarized monochromatic light beam;

a means for capturing a radiated image of said irradiation sensitive surface; and

a means for comparing said captured radiated surface image with an expected surface image.

12. An apparatus as described in claim 11, wherein said polarized monochromatic light beam is convergently focused onto said irradiation sensitive surface by said lens system, and wherein said polarized monochromatic light beam from said lens system is reflected from said surface and directed toward said means for capturing a radiated irradiation sensitive surface image.

13. An apparatus as described in claim 12, wherein said means for capturing a radiated surface image is a charge coupled device (CCD) camera.

14. An apparatus as described in claim 11, wherein said means for comparing said captured radiated surface image with said expected surface image is a computer.

15. An apparatus as described in claim 14, wherein said expected surface image is a computer stored expected image.

16. An apparatus as described in claim 14, wherein said computer also controls said means for generating a reflective pattern such that said reflective pattern is controlled to change in accordance with the determined position of said irradiation sensitive surface.

17. An apparatus as described in claim 11, wherein said irradiation sensitive surface is a photoresist coated semiconductor wafer surface, and wherein said polarized monochromatic light beam has a wavelength such that said photoresist is not exposed.

18. An apparatus as described in claim 17, wherein said source for providing a polarized monochromatic light beam is a helium-neon laser.

19. A method for micropatterning a surface, said surface having a property that is sensitive to irradiation, said method comprising the steps of

electronically generating a pattern from which polarized monochromatic light may be reflected;

irradiating said irradiation sensitive surface with polarized monochromatic light that is reflected from said electronically generated pattern so as to radiate an image of said electronically generated pattern;

determining the position of said irradiation sensitive surface with respect to said image of said electronically generated pattern; and

updating said electronically generated pattern to correspond with said determined irradiation sensitive surface position, such that said electronically generated pattern changes in accordance with any determined position movement said irradiation sensitive surface.

20. A method as described in claim 19, wherein said step of generating a pattern includes the substeps of:

displaying an image on a screen of a cathode ray tube (CRT);

optically connecting said CRT screen to a liquid crystal light value (LCLV); and

forming a reflective pattern of said CRT displayed image on a face of said LCLV.

21. A method as described in claim 19, wherein said step of irradiating said irradiation sensitive surface includes the substeps of:

providing a polarized monochromatic light beam;

collimating said polarized monochromatic light beam;

directing said collimated and polarized monochromatic light beam toward said electronically generated pattern;

reflecting said directed, collimated, and polarized monochromatic light beam from said electronically generated pattern;

directing said reflected, collimated, and polarized monochromatic light beam toward a lens system;

focusing said directed, reflected, collimated, and polarized monochromatic light beam onto said irradiation sensitive surface; and

exposing an image of said electronically generated pattern onto said irradiation sensitive surface with said focused, directed, reflected, and polarized monochromatic light beam.

22. A method as described in claim 19, wherein said step of determining the position of said irradiation sensitive surface includes the substeps of:

providing a polarized monochromatic light beam;

collimating said polarized monochromatic light beam;

directing said collimated and polarized monochromatic light beam toward a lens system;

focusing said directed, collimated, and polarized monochromatic light beam onto said irradiation sensitive surface;

reflecting said directed, focused, and polarized monochromatic light beam from said irradiation sensitive surface;

collimating said reflected, focused, and polarized monochromatic light beam;

directing said collimated, reflected, and polarized monochromatic light beam toward a charge coupled device (CCD) camera;

capturing said image of said irradiation sensitive surface from said directed, collimated, reflected, and polarized monochromatic light beam by said CCD camera; and

comparing said captured irradiation sensitive surface image to an expected surface image.

23. A method as described in claim 19, wherein said step of updating said generated pattern includes the substeps of:

determining an alignment of said radiated image of said electronically generated pattern with respect to said irradiation sensitive surface position by said step of determining the position of said light sensitive surface with respect to said polarized monochromatic radiation that radiates said electronically generated pattern image; and

controlling a cathode ray tube (CRT) screen to display an updated image from which said pattern is electronically generated, wherein said electronically generated pattern is updated from said CRT displayed updated image, wherein an image of said updated pattern is radiated onto said irradiation sensitive surface by said polarized monochromatic radiation, and wherein said updated radiated pattern image is properly aligned onto said irradiation sensitive surface.

24. A method as described in claim 19, additionally including the step of applying a coating of photoresist onto said surface to enable said surface to be irradiation sensitive.