Reticle inspecting apparatus capable of shortening an inspecting time

• US 6,400,839 B1
• Filed: 04/22/1999
• Issued: 06/04/2002
• Est. Priority Date: 04/24/1998
• Status: Active Grant

• Current Assignee: Coltera LLC
• Original Assignee: NEC Corporation
• Inventors: Takayama, Naohisa
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): AZARIAN, SEYED H
• Application Number:
  US09/296,266
• Time in Patent Office: 1,139 Days
• Field of Search: 382/145, 382/140, 382/141, 382/142, 382/143, 382/144, 382/146, 250/492.3, 716/19, 716/21
• US Class Current: 382/145
• CPC Class Codes: G03F 1/84 Inspecting

Abstract

A reticle inspecting apparatus comprises an image-pickup optical system (4, 5) for picking up an image of a pattern of a reticle mounted on an XY stage (3) to obtain a picked-up image pattern having first through N-th (N being an integer not smaller than two) frames, first through M-th (M being an integer not smaller than two and not greater than N) image comparators (71-74), a distributor (6) for distributing the first through the N-th frames of the picked-up image pattern to the first through the M-th image comparators (71-74) one after another, and an inspection controller (1) for converting CAD (Computer Aided Design) data used in drawing the pattern of the reticle into first through N-th intermediate data corresponding to the first through the N-th frames of the picked-up image pattern and for preliminarily transferring the first through the N-th intermediate data to the first through the M-th image comparators (71-74) one after another. The first through the M-th image comparators (71-74) compare the first through the N-th frames of the picked-up image pattern with first through N-th reference images produced from the first through the N-th intermediate data, respectively.

Claims

1. A reticle inspecting apparatus for detecting a pattern defect of a reticle for producing an integrated circuit, said apparatus comprising:

an XY stage on which said reticle is mounted;

an image-pickup optical system for picking up an image of a pattern of said reticle mounted on said XY stage to obtain a picked-up image pattern having first through N-th (N being an integer not smaller than two) frames;

first through M-th (M being an integer not smaller than two and not greater than N) image comparators;

a distributor for distributing said first through said N-th frames of said picked-up image pattern to said first through said M-th image comparators one after another; and

an inspection controller for converting CAD (Computer Aided Design) data used in drawing the pattern of said reticle into first through N-th intermediate data corresponding to said first through said N-th frames of said picked-up image pattern and for preliminarily transferring said first through said N-th intermediate data to said first through said M-th image comparators one after another;

said first through said M-th image comparators comparing said first through said N-th frames of said picked-up image pattern with first through N-th reference images produced from said first through said N-th intermediate data, respectively, to detect any defect in said first through said N-th frames of said picked-up image pattern.

2. A reticle inspecting apparatus as claimed in claim 1, wherein:

said image-pickup optical system comprises a laser-scanning optical system and a transmitting light detector, said laser-scanning optical system producing a laser beam to scan in a Y direction a surface of said reticle mounted on said XY stage and moving said XY stage in an X direction perpendicular to said Y direction, said transmitting light detector detecting a transmitting light obtained by transmission of said laser beam through said reticle to acquire each of said first through said N-th frames of said picked-up image pattern as a two-dimensional image pattern.

3. A reticle inspecting apparatus as claimed in claim 1, wherein:

said first through said M-th image comparators transfer to said inspection controller detection results obtained by detecting any defect in said first through said N-th frames of said picked-up image pattern, respectively.

4. A reticle inspecting apparatus as claimed in claim 1, wherein:

said distributor comprises first through M-th frame buffer memories for temporarily memorizing said first through said N-th frames of said picked-up image pattern, respectively;

said distributor distributing said first through said N-th frames memorized in said first through said M-th frame buffer memories, respectively, to said first through said M-th image comparators one after another.

5. A reticle inspecting apparatus for comparing reference and comparison die patterns of a reticle for producing an integrated circuit which are adjacent to each other, to detect any defect in said patterns, said apparatus comprising:

an XY stage on which said reticle is mounted;

an image-pickup optical system for picking up an image of said reference die pattern of said reticle mounted on said XY stage to obtain a picked-up reference die pattern having first through N-th (N being an integer not smaller than two) frames and thereafter picking up an image of said comparison die pattern of said reticle mounted on said XY stage to obtain a picked-up comparison die pattern having first through N-th frames;

first through M-th (M being an integer not smaller than two and not greater than N) image comparators; and

a distributor for distributing said first through said N-th frames of said picked-up reference die pattern to said first through said M-th image comparators one after another and thereafter distributing said first through said N-th frames of said picked-up comparison die pattern to said first through said M-th image comparators one after another;

said first through said M-th image comparators comprising first through M-th die memories for memorizing said first through said N-th frames of said picked-up reference die pattern as first through N-th memorized frames;

said first through said M-th image comparators comparing with said first through said N-th memorized frames said first through said N-th frames of said picked-up comparison die pattern which are transferred following said first through said N-th frames of said picked-up reference die pattern to detect any defect between each of said first through said N-th frames of said picked-up reference die pattern and each corresponding one of said first through said N-th frames of said picked-up comparison die pattern.

6. A reticle inspecting apparatus as claimed in claim 5, wherein:

said image-pickup optical system comprises a laser-scanning optical system and a transmitting light detector, said laser-scanning optical system producing a laser beam to scan in a Y direction a surface of said reticle mounted on said XY stage and moving said XY stage in an X direction perpendicular to said Y direction, said transmitting light detector detecting a transmitting light obtained by transmission of said laser beam through said reticle to acquire each of said first through said N-th frames of said picked-up reference die pattern and said first through said N-th frames of said picked-up comparison die pattern as a two-dimensional image pattern.

7. A reticle inspecting apparatus as claimed in claim 5, wherein:

said distributor comprises first through M-th frame buffer memories for temporarily memorizing said first through said N-th frames of said picked-up reference die pattern;

said distributor distributing to said first through said M-th image comparators one after another said first through said N-th frames of said picked-up reference die pattern which are memorized in said first through said M-th frame buffer memories, respectively;

said first through said M-th frame buffer memories thereafter temporarily memorizing said first through said N-th frames of said picked-up comparison die pattern;

said distributor distributing to said first through said M-th image comparators one after another said first through said N-th frames of said picked-up comparison die pattern which are memorized in said first through said M-th frame buffer memories, respectively.

8. A reticle pattern defect inspection apparatus, comprising:

(a) an image input distributor configured to input a picked-up image of a reticle pattern as first through N-th (1-N frames), wherein N is an integer not smaller than two; and

(b) first through M-th image comparators (1-M comparators), wherein M is an integer not smaller than two and not greater than N, configured to process an image in parallel, said processing to include receiving said 1-N frames from said image input distributor, comparing first through N-th data units of reference image data corresponding to said 1-N frames with said 1-N frames, and reporting any defects detected in said 1-N frames.

9. A reticle pattern defect inspection method comprising:

(a) inputting a picked-up image of a reticle pattern as first through N-th frames (1-N frames), wherein N is an integer not smaller than two;

(b) transmitting said 1-N frames to first through M-th image comparators (1-M comparators), wherein M is an integer not smaller than two and not greater than N, said 1-M comparators processing an image in parallel; and

(c) comparing said 1-N frames with first through N-th data units of reference image data corresponding to said 1-N frames, and reporting any defects detected in said 1-N frames.

10. A computer readable medium incorporating program instructions configured to enable a processor to:

(a) input a picked-up image of a reticle pattern as first through N-th frames (1-N frames), wherein N is an integer not smaller than two;

(b) transmit said 1-N frames to first through M-th image comparators (1-M comparators), wherein M is an integer not smaller than two and not greater than N, said 1-M comparators processing an image in parallel; and

(c) compare said 1-N frames with first through N-th data units of reference image data corresponding to said 1-N frames, and report any defects detected in said 1-N frames.