Defect Detection and Response

• US 20100074515A1
• Filed: 12/17/2008
• Published: 03/25/2010
• Est. Priority Date: 02/05/2008
• Status: Abandoned Application

• Current Assignee: KLA-Tencor Corporation (KLA Corporation)
• Original Assignee: KLA-Tencor Corporation (KLA Corporation)
• Inventors: Vaez-Iravani, Medhi, Ngai, Samuel S.H., Levy, Ady, Zhao, Guoheng, Zapalac, George H. JR., Dharmadhikari, Vineet
• Application Number:
  US12/336,704
• Publication Number:
  US 20100074515A1
• Time in Patent Office: Days
• US Class Current: 382/149
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: G02F 1/1309 Repairing; Testing
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

To increase inspection throughput, the field of view of an infrared camera can be moved over the sample at a constant velocity. Throughout this moving, a modulation (such as optical or electrical) can be provided to the sample and infrared images can be captured using the infrared camera. Moving the field of view, providing the modulation, and capturing the infrared images can be synchronized. The infrared images can be filtered to generate the time delay lock-in thermography, thereby providing defect identification. In one embodiment, this filtering accounts for the number of pixels of the infrared camera in a scanning direction. For the case of optical modulation, a dark field region can be provided for the field of view throughout the moving, thereby providing an improved signal-to-noise ratio during filtering. Localized defects can be repaired by a laser integrated into the detection system or marked by ink for later repair in the production line.

Claims

1. A system for performing time delay lock-in thermography on a sample, the system comprising:

an infrared camera for capturing images of the sample,

scanning components for moving a field of view of the infrared camera over the sample at a constant velocity,

modulation components for providing a modulation to the sample when moving the field of view,

a clock source for synchronizing the capturing of images, the moving of the field of view, and the providing of the modulation,

an image processor for receiving the captured images and generating a time delay lock-in thermography image to provide detection of a defect, and

instrumentation to at least one of repair the defect, and mark a position of the defect for later repair.

2. The system of claim 1, wherein the instrumentation repairs the defect with a laser that electrically isolates the defect.

3. The system of claim 1, further including one of a light shield and a light pipe for providing a dark field region for the field of view.

4. The system of claim 1, wherein the image processor includes filters that implement two equations:

5. A system for performing dark field, lock-in thermography on a sample, the system comprising:

an infrared camera for capturing images of the sample,

positioning components for positioning a field of view of the infrared camera over the sample,

optical modulation components for providing an optical modulation to the sample after positioning the field of view,

a light directing component for providing a dark field region for the field of view,

a clock source for synchronizing the capturing of images and the providing of the modulation,

an image processor for receiving the captured images and generating a time delay lock-in thermography image to detect a defect on the sample, and

instrumentation to at least one of repair the defect, and mark a position of the defect for later repair.

6. The system of claim 5, wherein the instrumentation repairs the defect with a laser that electrically isolates the defect.

7. A tool for detecting and taking action on a defect in a moving web of photovoltaic material without stopping the movement of the web, the tool comprising:

a detection module for detecting the defect in the web as it is moving, the detection module comprising a linear array of sensors disposed across the web of photovoltaic material perpendicular to the movement of the web, where each sensor in the linear array inspects an incremental portion of a width of the web,

an action module for taking a predetermined action on the defect in the web as it is moving, the action module comprising a linear array of actors disposed across the web of photovoltaic material perpendicular to the movement of the web, where each actor in the linear array acts upon an associated one of the incremental portions of the width of the web,

a common frame to which both the detection module is mounted and the action module is mounted, where the detection module is disposed at a known distance from and in an upstream position to the action module relative to the movement of the web, and

a controller for determining a position of the defect as detected by the detection module, at least one of receiving and detecting a speed of the moving web, and for instructing the action module to take action on the defect at an appropriate point in time when the defect is disposed within an action range of the action module, based at least in part upon the speed of the moving web and the known distance between the detection module and the action module.

8. The tool of claim 7, wherein the detection module detects the defect using a voltage detection method.

9. The tool of claim 7, wherein the detection module detects the defect using a hot spot detection method.

10. The tool of claim 7, wherein the action module repairs the defect.

11. The tool of claim 7, wherein the action module repairs the defect by laser isolating the defect.

12. The tool of claim 7, wherein the action module repairs the defect by forming a nonconductive surface on top of the defect.

13. The tool of claim 7, wherein the action module physically marks the defect without repairing the defect.

14. A method of performing time delay lock-in thermography on a sample, the method comprising the steps of:

moving a field of view of an infrared camera over the sample, the moving being at a constant velocity,

providing a modulation to the sample throughout the moving,

capturing infrared images using the infrared camera throughout the moving, wherein moving the field of view, providing the modulation, and capturing the infrared images are synchronized,

filtering the infrared images to generate a time delay lock-in thermography image, thereby providing defect identification, and

at least one of repairing a defect and marking a position of the defect for later repair.

15. The method of claim 14, wherein the modulation is one of optical and electrical.

16. The method of claim 14, wherein the sample is one of a semiconductor wafer, a solar cell, a solar panel, a continuous web, and a printed circuit board.

17. The method of claim 14, wherein filtering includes performing two equations:

18. The method of claim 14, further including providing a dark field illumination for the field of view throughout the moving.

19. The method of claim 14, wherein moving includes using at least one of a scanning stage, bi-directional linear stages in a gantry system, a gantry bridge, a conveyor, and at least one roller.

20. The method of claim 14, wherein repairing the defect is accomplished with a laser that electrically isolates the defect.