Inspection system and device manufacturing method using the same

• US 5,767,962 A
• Filed: 11/25/1996
• Issued: 06/16/1998
• Est. Priority Date: 01/13/1994
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Masayuki, Miyazaki, Kyoichi, Tsuji, Toshihiko, Takeuchi, Seiji, Yoshii, Minoru, Nose, Noriyuki
• Primary Examiner(s): Pham, Hoa Q.
• Application Number:
  US08/755,352
• Time in Patent Office: 568 Days
• Field of Search: 356/237, 356/239, 356/394, 356/429-431, 250/561, 250/563, 250/572, 359/205-219
• US Class Current: 356/237.2
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence

Abstract

An inspection system includes a light source, a scanning device for scanning a surface to be inspected, with light from the light source, wherein the scanning device includes an optical member disposed with inclination with respect to a primary scan direction, the optical member being adapted to provide a convergent light being converged to form a spot at a distance changeable with the position of a scan, and a light receiving device for receiving scattered light from the surface.

Claims

1. An inspection system for inspecting a surface of an object, said system comprising:

a light source;

a scanning lens system for linearly scanning the surface with light from said light source, said scanning lens system having an asymmetrical refracting power in a direction of the scan, for providing a convergent light beam, to be focused on the surface to image a spot on the surface at a focal distance which is changeable in accordance with the position of scan on the surface; and

a detector for receiving light from the surface.

2. A system according to claim 1, wherein said scanning lens system further comprises a scanning mirror and further comprising a lens having a shape asymmetrical with respect to an optical axis.

3. A system according to claim 1, wherein said scanning lens system further comprises a scanning mirror and further comprising a hologram member having a changing grating pitch.

4. A system according to claim 1, wherein said scanning lens system further comprises a scanning mirror and a lens movable along an optical axis for directing the light from said light source to said scanning mirror.

5. A system according to claim 1, wherein said scanning lens system further comprises deflecting means for reflectively deflecting received light in different directions with different refractivities.

6. A device manufacturing method usable with a reticle having a device pattern, said method comprising the steps of:

scanning a surface of the reticle to be inspected, with light from a light source and through a scanning lens system having an asymmetrical refracting power in a direction of the scan, wherein the scanning lens system provides a convergent light beam being focused on the surface to image a spot on the surface at a focal distance which is changeable in accordance with the position of scan on the surface;

receiving, through light receiving means, scattered light from the surface and performing inspection of the reticle on the basis of the result of the light reception; and

transferring the device pattern of the inspected reticle to a substrate through a lithographic process.

7. An inspection method for inspecting a surface of an object, said method comprising the steps of:

providing a light beam;

deflecting the light beam to perform a linear scan of the surface;

causing the light beam to be focused on the surface to image a spot on the surface at a focal distance which is changeable in accordance with the position of scan on the surface, by use of a scanning lens system having an asymmetrical refracting power in the direction of the scan; and

detecting light from the surface.