System and method for locating irregular edges in image data

• US 7,046,837 B2
• Filed: 08/21/2002
• Issued: 05/16/2006
• Est. Priority Date: 06/13/2000
• Status: Expired due to Term

• Current Assignee: Onto Innovation Inc.
• Original Assignee: August Technology Corporation (Onto Innovation Inc.)
• Inventors: Chang, Chu-Yin, Guest, Clyde Maxwell
• Primary Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US10/224,919
• Publication Number:
  US 20020191832A1
• Time in Patent Office: 1,364 Days
• Field of Search: 382/190, 382/199, 382/251, 382/145, 382/266, 382/300, 382/173, 382/148, 382/141, 382/279, 382/293, 700/279, 700/95, 250/559.39, 250/559.4, 702/35, 356/237.1, 356/239.1, 356/394, 219/121.64
• US Class Current: 382/145
• CPC Class Codes: G06T 2207/10056 Microscopic image
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume

Abstract

A system for processing image data, such as an image of a die cut from a silicon wafer, is provided. The system includes an irregular edge detection system, which can locate edge data of a feature of the image data, such as the edge of a probe mark in a bond pad. A feature area calculation system is connected to the irregular edge detection system, such as by accessing data stored by the irregular edge detection system. The feature area calculation system can receive the edge data of the feature and determining the area of the feature, such as by summing normalized pixel area values. The irregular edge detection system uses interpolation to locate edges that occur between the centerpoints of adjacent pixels.

Claims

1. A system for inspecting components comprising:

an irregular edge detection system receiving image data and generating feature pixel data by assigning a brightness value to regular and irregular features in the image data;

a feature edge location system receiving the feature pixel data and generating sub-pixel edge data; and

a feature area calculation system receiving the sub-pixel edge data and generating feature area data using the sub-pixel edge data.

2. The system of claim 1 wherein the feature area calculation system further comprises a contrast selection receiving the feature pixel data and generating sub-pixel range data.

3. The system of claim 1 wherein the feature area calculation system further comprises a pixel comparator system receiving the feature pixel data and generating pixel area data.

4. The system of claim 1 wherein the feature area calculation system further comprises an area register receiving the feature pixel data and generating feature area data.

5. The system of claim 1 wherein the feature area calculation system further comprises an area register receiving the feature pixel data and generating probe mark area data.

6. The system of claim 1 wherein the irregular edge detection system further comprises a feature box system receiving the feature pixel data and generating feature box data.

7. The system of claim 1 wherein the brightness value is a variation in brightness between pixels in the image data.

8. The system of claim 1 wherein the feature pixel data includes a first brightness value assigned to a pixel within the feature and a second brightness value assigned to a pixel outside the feature.

9. A system for inspecting components comprising:

a brightness contrast selection system receiving image data and generating sub-pixel range data for regular and irregular features;

a pixel comparator receiving the sub-pixel range data and pixel data and generating sub-pixel edge data; and

an area register receiving the image data and generating feature area data.

10. The system of claim 9 wherein the sub-pixel edge data further comprises sub-pixel area data.

11. The system of claim 9 further comprising an area register receiving the image data and generating probe mark area data.

12. A method for inspecting components comprising:

receiving a plurality of pixels of image data;

determining a first brightness value of a pixel within a feature;

determining a second brightness value of a pixel outside of the feature;

identifying an edge pixel wherein an edge lies within an area bounded by the edge pixel; and

generating area data that is less than an area bounded by a standard pixel.

13. The method of claim 12 further comprising using the sub-pixel edge data to calculate feature area data.

14. The method of claim 12 wherein generating sub-pixel edge data comprises generating edge coordinate data.

15. The method of claim 12 wherein identifying the edge pixel comprises:

identifying a pixel as the edge pixel if the brightness of the pixel is between the first brightness value and the second brightness value.

16. The method of claim 12 wherein generating area data comprises:

generating area data based on the first brightness value and the second brightness value.

17. The method of claim 16 wherein generating the area data based on the first brightness value and the second brightness value comprises:

assigning a normalized area of 1.0 to the first brightness value;

assigning a normalized area of 0.0 to the second brightness value; and

assigning a normalized area to the edge pixel based on the ratio of the difference between the edge pixel brightness and the second brightness value to the difference between the first brightness value and the second brightness value.

18. The method of claim 12 further comprising using the sub-pixel edge data to calculate probe mark area data.

19. The method of claim 12 wherein identifying the edge pixel wherein the edge lies within the area bounded by the edge pixel comprises:

determining a pixel brightness variation D2 of a first row of pixels;

determining a pixel brightness variation D3 of a second row of pixels; and

identifying the edge pixel as the pixel where D3 is greater than D2.