Inspecting method and apparatus for repeated micro-miniature patterns

• US 6,944,325 B2
• Filed: 09/08/2003
• Issued: 09/13/2005
• Est. Priority Date: 08/07/1997
• Status: Expired due to Fees

• Current Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Tech Electronics Engineering Co., Ltd. (Hitachi, Ltd.)
• Inventors: Sugimoto, Aritoshi, Taguchi, Junichi, Inoue, Yuko, Ikoto, Masami, Shinke, Wakana, Watanabe, Tetsuya
• Primary Examiner(s): AHMED, SAMIR ANWAR
• Application Number:
  US10/656,221
• Publication Number:
  US 20040047500A1
• Time in Patent Office: 736 Days
• Field of Search: 382/141, 382/145, 382/147, 382/148, 382/149, 348/87, 348/126, 356/237.3, 356/237.4, 356/237.5, 356/237.2, 250/559.04, 250/559.41, 250/559.42, 250/559.43, 250/559.44, 250/559.45, 250/559.46, 250/559.05, 250/559.06, 250/559.08, 250/559.39, 250/559.4, 438/16, 702/40, 702/82, 702/172, 702/459
• US Class Current: 382/149
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

An apparatus for inspecting foreign matter in repeated micro-miniature patterns formed upon a surface of an object to be inspected, comprising: an inspection light illuminating device for irradiating an inspection light directed upon the surface of the object to be inspected, on which the repeated micro-miniature patterns are formed; a scattered light detector for detecting scattered light of the inspection light being scattered upon the surface said object to be inspected; means for obtaining a first information related to a foreign matter attaching upon the surface of said object to be inspected, which is obtained on a basis of the detection of said scattered light by said scattered light detector; an illumination means for applying a bright field illumination upon the surface of the object to be inspected, on which the repeated micro-miniature patterns are formed; means for picking up the image of the foreign matter, under a bright field illumination by said illumination means; means for obtaining a second information related to said foreign matter, depending upon an image of said foreign matter, which is obtained on a basis of said picking up of the image by said image picking up means under the bright field illumination; and means for displaying said first information and said second information, both being related to said foreign matter, on a display screen thereof.

Claims

1. A method for inspecting foreign matters in or on repeated micro-miniature patterns formed upon a surface of an object to be inspected, comprising following steps:

obtaining an object image by picking up the image of the micro-miniature pattern, under a bright field illumination, at a coordinate position on the surface of said object to be inspected, which is designated previously;

obtaining a reference image by picking up the image of the micro-miniature pattern, under a bright field illumination, at an another coordinate position on the surface of said object to be inspected, which is different from but corresponding to said coordinate position mentioned in the above step;

obtaining at least one of (a) a difference image between said object image and said reference image and (b) a summation image of said object image and said reference image; and

deciding a presence of a foreign matter at the coordinate position on said object to be inspected, which is previously designated, on a basis of at least one of (a) a difference between a distance between separate images of the foreign matter adjacent to each other and a width of said repeated micro-miniature patterns on the difference image, (b) the summation image being made on the micro-miniature pattern and the foreign matter to be compared to a predetermined threshold, and (c) colors of said different images adjacent to each other of the foreign matter.

2. A method for inspecting foreign matters, as defined in claim 1, wherein the coordinate position on the surface of said object to be inspected which is designated previously, is a position of existing said foreign matter, which is defined by detecting a scattered light from the surface of the repeated micro-miniature pattern under a dark field when an inspection light is illuminated upon said object to be inspected from a light source.

3. A method for inspecting foreign matters, as defined in claim 1, wherein on the surface of said object to be inspected are formed at least two or more of same patterns repeatedly, and the position of said reference image is equal to that of said object image to inspected on the coordinates on each of said at least two or more of patterns.

4. A method for inspecting foreign matters, as defined in claim 1, further comprising a step for displaying a result of a decision made in the deciding step.

5. A method for inspecting foreign matters, as defined in claim 1, further comprising a step of calculating a size of defect based on a summation of a normal length of difference images decided as a defect and a width of said repeated micro-miniature patterns.

6. A method for inspecting foreign matters, as defined in claim 1, further comprising a step in which a difference of length between a length of adjacent difference images is longer than a width of said repeated micro-miniature patterns for deciding a defect as a non-fatal defect, and in which a difference of length between a length of adjacent difference images is shorter than a width of said repeated micro-miniature patterns for deciding a defect as a fatal defect.

7. A method for inspecting foreign matters as defined in claim 1, wherein the step of obtaining includes obtaining (a) difference image between said object and said reference image, and the step of deciding includes deciding the presence of a foreign matter at the coordinate position on said object to be inspected, which is previously designated, on the basis of (a) a difference between a distance between separate images of the foreign matter adjacent to each other and the width of said repeated micro-miniature patterns on the difference image.

8. A method for inspecting foreign matters, as defined in claim 1, wherein the step of obtaining includes obtaining (b) a summation image of said object image and said reference image, and the step of deciding a presence of a foreign matter at the coordinate position on said object to be inspected, which is previously designated, is decided on the basis of (b) the summation image being made on the micro-miniature pattern and the foreign matter to be compared to a predetermined threshold.

9. A method for inspecting foreign matters as defined in claim 1, wherein the step of obtaining includes obtaining (a) a difference image between said object image and said reference image, and the step of deciding a presence of a foreign matter at the coordinate position on said object to be inspected, which is previously designated, includes deciding on the basis of (c) colors of said different images adjacent to each other of the foreign matter.

10. A method for inspecting foreign matters, as defined in claim 5, further comprising a step for displaying a result of a decision made in the deciding step.

11. A method for inspecting foreign matters, as defined in claim 6, further comprising a step for displaying a result of a decision made in the deciding step.

12. A method for inspecting foreign matters, as defined in claim 7, further comprising a step for displaying a result of a decision made in the deciding step.

13. A method for inspecting foreign matters, as defined in claim 8, further comprising a step for displaying a result of a decision made in the deciding step.

14. A method for inspecting foreign matters, as defined in claim 9, further comprising a step for displaying a result of a decision made in the deciding step.