Fiber optic darkfield ring light

• US 20050007792A1
• Filed: 07/09/2004
• Published: 01/13/2005
• Est. Priority Date: 07/11/2003
• Status: Active Grant

• Current Assignee: Rudolph Technologies Incorporated
• Original Assignee: August Technology Corporation (Rudolph Technologies Incorporated)
• Inventors: Li, Falai
• Granted Patent: US 7,220,034 B2
• Time in Patent Office: Days
• US Class Current: 362/556
• CPC Class Codes: G01N 2021/8822 Dark field detection
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides
• CPC Class Codes: G01N 2201/0826 Fibre array at source, distributing
• CPC Class Codes: H01L 21/67288 Monitoring of warpage, curvature, damage, defects or the like

Abstract

A fiber optic darkfield ring light with many angled fiber optic light lines with direct illumination in a very small package. The fiber optic darkfield ring light includes a base with multiple light heads and multiple light covers attached thereto, a main cover, an optional cord grip, and an optional hood. It incorporates multiple fiber optic line arrays positioned at low angle and used in conjunction with a strobe light source.

Claims

1. A darkfield illuminator, comprising:

a base;

a plurality of light heads attached to the base;

a plurality of fiber optic lines; and

wherein each of the light heads is configured to hold a set of the fiber optic lines.

2. The darkfield illuminator of claim 1, wherein the base includes a recess formed therein.

3. The darkfield illuminator of claim 2, wherein the recess is substantially cylindrical in shape.

4. The darkfield illuminator of claim 2, wherein the recess is defined by a bottom recess surface and a wall substantially surrounding the bottom recess surface.

5. The darkfield illuminator of claim 4, wherein the bottom recess surface includes a first surface portion that is angled with respect to a surface to be illuminated.

6. The darkfield illuminator of claim 5, wherein the light heads are attached to the first surface portion in a substantially circular arrangement, and are configured to provide light from the fiber optic lines toward a center of the substantially circular arrangement.

7. The darkfield illuminator of claim 6, wherein the first surface portion and the light heads attached thereto are angled at an angle of between about 5 and 25 degrees to provide light at a corresponding angle of between about 5 and 25 degrees.

8. The darkfield illuminator of claim 6, wherein the first surface portion and the light heads attached thereto are angled at an angle of about 15 degrees to provide light at an angle of about 15 degrees.

9. The darkfield illuminator of claim 6, wherein the bottom recess surface includes a second surface portion extending outward from and substantially surrounding the first surface portion, and wherein the second surface portion and the wall define a channel for routing fiber optic lines to the light heads.

10. The darkfield illuminator of claim 9, wherein the second surface portion is substantially parallel to a surface to be illuminated.

11. The darkfield illuminator of claim 9, wherein the first surface portion and the second surface portion are each ring shaped.

12. The darkfield illuminator of claim 6, wherein the light heads are each tapered.

13. The darkfield illuminator of claim 1, wherein the plurality of light heads includes at least eight light heads.

14. The darkfield illuminator of claim 1, wherein the set of fiber optic lines held by each of the light heads includes a plurality of fiber optic lines that are arranged in a light line configuration, such that the plurality of light heads provides a corresponding plurality of lines of light.

15. The darkfield illuminator of claim 1, wherein the base is less than about one-half inch in height.

16. The darkfield illuminator of claim 1, wherein the base is about 0.35 inches in height.

17. An automated inspection system for inspecting a substrate, comprising:

a darkfield illumination device for illuminating the substrate, the darkfield illumination device including a base having a recess formed therein, the base including a bottom surface at a bottom of the recess, the bottom surface including a first surface portion that is angled with respect to a surface to be illuminated, the darkfield illumination device including a plurality of light heads attached to the first surface portion in a substantially circular arrangement, the light heads each including a plurality of fiber optic lines for providing light toward a center of the substantially circular arrangement at an angle corresponding to the angle of the first surface portion;

a substrate provider for providing the substrate within the substantially circular arrangement of light heads;

a visual inspection device for capturing images of the substrate provided by the substrate provider; and

a controller for identifying defects in the substrate based on the captured images.

18. The automated inspection system of claim 17, wherein the recess is substantially cylindrical in shape.

19. The automated inspection system of claim 17, wherein the recess is defined by the bottom surface and a wall substantially surrounding the bottom surface.

20. The automated inspection system of claim 17, wherein the first surface portion and the light heads attached thereto are angled at an angle of between about 5 and 25 degrees to provide light at a corresponding angle of between about 5 and 25 degrees.

21. The automated inspection system of claim 17, wherein the first surface portion and the light heads attached thereto are angled at an angle of about 15 degrees to provide light at an angle of about 15 degrees.

22. The automated inspection system of claim 17, wherein the bottom surface includes a second surface portion extending outward from and substantially surrounding the first surface portion, and wherein the second surface portion and a recess wall define a channel for routing fiber optic lines to the light heads.

23. The automated inspection system of claim 22, wherein the second surface portion is substantially parallel to a surface to be illuminated.

24. The automated inspection system of claim 22, wherein the first surface portion and the second surface portion are each ring shaped.

25. The automated inspection system of claim 17, wherein the light heads are each tapered.

26. The automated inspection system of claim 17, wherein the plurality of light heads includes at least eight light heads.

27. The automated inspection system of claim 17, wherein the plurality of fiber optic lines in each of the light heads are arranged in a light line configuration, such that the plurality of light heads provide a corresponding plurality of lines of light.

28. The automated inspection system of claim 17, wherein the darkfield illumination device is configured to strobe based on a velocity of the substrate.

29. A method of providing darkfield illumination, the method comprising:

providing a base having a recess formed therein, the recess defined by a bottom surface and a wall substantially surrounding the bottom surface, the bottom surface including a first surface portion that is angled with respect to a surface to be illuminated;

attaching a plurality of light heads to the first surface portion in a substantially circular arrangement, the light heads each including a plurality of fiber optic lines; and

transmitting light through the fiber optic lines of each light head, thereby providing light toward a center of the substantially circular arrangement at an angle corresponding to the angle of the first surface portion.

30. An illuminator comprising:

a base with multiple light heads attached thereto; and

fiber optics provided in each of the multiple heads.