Method of soft x-ray imaging

• US 5,987,092 A
• Filed: 03/11/1998
• Issued: 11/16/1999
• Est. Priority Date: 07/18/1996
• Status: Expired due to Fees

• Current Assignee: University of Hawai'i
• Original Assignee: University of Hawai'i
• Inventors: Pong, William
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US09/038,806
• Time in Patent Office: 615 Days
• Field of Search: 378/36
• US Class Current: 378/36
• CPC Class Codes: G01B 15/06 for measuring the deformation in a solid
• CPC Class Codes: G03F 1/22 Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
• CPC Class Codes: G03F 1/84 Inspecting

Abstract

A method for inspecting masks used in x-ray lithography is described. An x-ray lithography mask is placed over a glass surface, followed by exposure of the mask and glass surface to soft x-rays. Portions of the mask absorb the soft x-rays while other portions of the mask, corresponding to circuit elements, allow the soft x-rays to strike the glass surface. The soft x-rays striking the glass surface cause the glass surface to darken, thereby forming an image of the circuit pattern in the glass surface corresponding to the stenciled circuit in the mask. An inspection of the image can reveal any defects in the x-ray lithography mask.

Claims

1. A method for forming a hologram in a glass surface, comprising the steps of:

a. providing a soft x-ray laser source, a glass surface, a splitting means and an object;

b. positioning said splitting means between said glass surface and said soft x-ray laser source;

c. projecting a laser beam from said soft x-ray laser source toward said splitting means; and

d. splitting said laser beam into first and second coherent beams whereby said first beam travels toward and strikes said glass surface and said second beam reflects off said object and travels toward and strikes said glass surface whereby a hologram image of said object is formed on said glass surface.

2. The method of claim 1, wherein said splitting means comprises mirrors.

3. The method of claim 1, wherein said splitting means comprises a surface layer coating of Molybdenum-Silicon.

4. A glass surface having a hologram produced according to the method of claim 1.

5. A method of forming an image on a glass surface using soft x-rays, comprising the steps of:

a) providing a source of soft x-rays, a glass surface, and an object; and

b) exposing said glass surface to soft x-rays from said source of soft x-rays, whereby an image is formed on said glass surface, said image corresponding to areas on said glass surface exposed to said soft x-rays, wherein said exposing further comprises the steps of;

i) positioning a splitting means between said glass surface and said source of soft x-rays; and

ii) splitting said soft x-rays into two coherent beams whereby i) a first beam directly strikes said glass surface and ii) a second beam strikes an object and is then reflected toward and strikes said glass surface, whereby said first and second beams discolor said glass surface in such a way as to form an image of said object on said glass surface.

6. A glass surface having an image produced according to the method of claim 5.

7. The method of claim 5, wherein said source of soft x-rays is a soft x-ray laser.

8. The method of claim 5, wherein said source of soft x-rays is an x-ray tube.

9. The method of claim 5, wherein said splitting means comprises mirrors.