Surface inspection apparatus and method

• US 6,313,913 B1
• Filed: 11/23/1999
• Issued: 11/06/2001
• Est. Priority Date: 11/26/1998
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nakagawa, Yumi, Komatsu, Koichiro
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Nguyen, Sang H.
• Application Number:
  US09/447,691
• Time in Patent Office: 714 Days
• Field of Search: 356/237.1, 356/237.2, 356/237.3, 356/237.5, 356/237.4, 356/237.6, 356/394, 356/239.7, 356/239.8, 250/225, 250/560, 250/561
• US Class Current: 356/237.2
• CPC Class Codes: G01N 2021/9513 Liquid crystal panels
• CPC Class Codes: G01N 2021/95676 Masks, reticles, shadow masks
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence

Abstract

A surface inspection apparatus is provided which uses at least two sets of surface inspection systems each comprising with a paired surface illumination device (A1, B1) and detection device (A2, B2), with each set of illumination devices and detection devices creating their own irradiation regions (51A, 51B) and detection regions (23A,23B), in which the irradiation and detection regions of one pair of illumination and detection devices does not over lap the illumination and detection regions of the adjacent pair of illumination and detection devices. The surface illumination devices preferably project light at an angle of 80° or more with respect to a normal to the surface being inspected (21). The detection devices detect light scattered by dust or defects on the surface to be inspected. The surface to be inspected can be moved in a direction perpendicular to the direction of the illumination and detection regions on the surface being inspected. Thus, the entire surface can be inspected. The inspection device and method can also be adapted for use in a liquid crystal display manufacturing operation.

Claims

1. A liquid crystal display manufacturing method comprising:

inspecting a reticle having a pattern thereon for defects and foreign matter adhering to the reticle; and

exposing a pattern of the reticle onto a photosensitive substrate;

wherein said step of inspecting the reticle comprises;

a. irradiating the reticle with a first light beam from a first light irradiation system to form a first band-shaped irradiation region along a predetermined first direction on the reticle;

b. receiving scattered light from said first band-shaped irradiation region with a first light receiving system;

c. irradiating the reticle with a second light beam from a second light irradiation system to form a second band-shaped irradiation region along said first direction on the reticle;

d. receiving scattered light from said second band-shaped irradiation region with a second light receiving system; and

e. moving the reticle relative to said first and second light irradiation systems along a second direction substantially orthogonal to said first direction;

f. wherein said first band-shaped irradiation region and said second band-shaped irradiation region are separated by a predetermined distance along said second direction so as to prevent said first light irradiation system from receiving scattered light from said second band-shaped irradiation region and prevent said second light irradiation system from receiving scattered light from said first band-shaped irradiation region.

2. A method according to claim 1, wherein the first band-shaped irradiation region and the second band-shaped irradiation region jointly scan the reticle without any gaps.

3. A method according to claim 1, wherein:

a. said first light receiving system has a first optical system that forms an image of said first band-shaped irradiation region in a first imaging plane, and has a first light receiving member having a first light receiving surface at or near said first imaging plane;

b. said second light receiving system has a second optical system that forms an image of said second band-shaped irradiation region in a second imaging plane, and has a second light receiving member having a second light receiving surface at or near said second imaging plane;

c. said predetermined distance is set so that a first band-shaped light receiving take-in region on the reticle corresponding to said first light receiving surface with respect to said first light receiving system does not overlap said second irradiation region, and so that a second band-shaped light receiving take-in region on the reticle corresponding to said second light receiving surface with respect to said second light receiving system does not overlap said first irradiation region; and

d. b1 is the width of said first band-shaped irradiation region, c1 is the width of said first band-shaped light receiving take-in region, b2 is the width of said second band-shaped irradiation region and c2 is the width of said second band-shaped light receiving take-in region, a distance between a center of said first-band-shaped irradiation region and a center of said second band-shaped light receiving take-in region is greater then the value of half of (b1+c2), and a distance between the center of said second band-shaped irradiation region and the center of said first band-shaped light receiving take-in region is greater than the value of half of (b2+c1).

4. A method according to claim 1, wherein:

a. said first light receiving system has a first optical system that forms an image of said band-shaped irradiation region in a first imaging plane, and has a first light receiving member having a first light receiving surface at or near said first imaging plane;

b. said second light receiving system has a second optical system that forms an image of said second band-shaped irradiation region in a second imaging plane, and has a second light receiving member having a second light receiving surface at or near said second imaging plane;

c. a width of said first band-shaped irradiation region is narrower than a width of a first band-shaped light receiving take-in region on said reticle corresponding to said first light receiving surface with respect to said first light receiving system, and a width of said second band-shaped irradiation region is narrower than a width of a second band-shaped light receiving take-in region on the reticle corresponding to said second light receiving surface with respect to said second light receiving system; and

d. said first band-shaped light receiving take-in region and said second band-shaped light receiving take-in region on said reticle do not overlap.

5. A method according to claim 1, wherein said first light irradiation system projects said first light beam toward the reticle at an angle of incidence in the range of between 80°

to 90°

, and said second light irradiation system projects said second light beam toward the reticle at an angle of incidence of between 80°

to 90°

, and wherein the angle of incidence is the angle formed between the normal to the reticle and the axis of illumination of the first and second light irradiation systems, respectively.

6. A liquid crystal display manufacturing method comprising:

inspecting a reticle having a pattern thereon for defects and foreign matter adhering to the reticle; and

exposing a pattern of the reticle onto a photosensitive substrate;

wherein said step of inspecting the reticle comprises;

a. forming a first illumination region on the reticle;

b. detecting light from said first illumination region with a first detection region;

said first detection region having a predetermined size on the reticle that is different from a size of said first illumination region on the reticle;

c. forming a second illumination region on the reticle; and

d. detecting light from said second illumination region with a second detection region, said second detection region having a predetermined size that is different from a size of said second illumination region.

7. A method according to claim 6, wherein:

said step of detecting scattered light from the first illumination region includes detecting scattered light from a first detection region which includes said first illumination region and wherein said first detection region is larger than said first illumination region; and

said step of detecting scattered light from the second illumination region includes detecting scattered light from a second detection region which includes said second illumination region and wherein said second detection region is larger than said second illumination region.

8. A method according to claim 7, wherein said step of forming said first and second illumination regions involves illuminating said first and second illumination regions so that the first and second illumination regions do not overlap on the reticle.

9. A method according to claim 6, wherein said step of forming said first and second illumination regions involves illuminating said first and second illumination regions so that the first and second illumination regions do not overlap on the reticle.

10. A liquid crystal display manufacturing method comprising:

inspecting a reticle having a pattern thereon for defects and foreign matter adhering to the reticle; and

exposing a pattern of the reticle onto a photosensitive substrate;

wherein said step of inspecting the reticle comprises;

forming a first illumination region on the reticle;

forming a second illumination region on the reticle without overlapping said first illumination region;

detecting scattered light from said first illumination region without receiving scattered light from said second illumination region; and

detecting scattered light from said second illumination region without receiving scattered light from said first illumination region.

11. A method according to claim 10, wherein said step of detecting scattered light from said first illumination region comprises the step of using a first detection region having a size on the reticle that is different from a size of said first illumination region;

and

wherein said step of detecting scattered light from said second illumination region comprises the step of using a detection region having a size on the reticle that is different from a size of said second illumination region.