Focus tracking techniques for inspection system
AssigneeOnto Innovation Inc.
InventorNoah Christopher Bock
Life of this patent
Estimating the term…
Abstract
An improved focus tracking system for an inspection system that positions a line ahead of the imaging field of view in the scan direction and dynamically actuates an optical element to reposition the line when the scan direction changes is provided. Current systems fail to provide leading focus information or adjust to allow for a high-speed scan. The focus tracking system may be used in inspection systems for substrates such as panels and wafers, through-glass vias (TGVs), as well as various electronic devices.
Claims20
A focus tracking system for an inspection system that improves focus information and adjusts positions in a scan, the focus tracking system comprising:
- an optical displacement sensor configured to generate light in the form of a line;
- an optical element configured to project the line onto a surface of an article under inspection;
- a position sensing device configured to detect light representing a reflected line from the surface of the article under inspection;
- and
- a controller configured to:
- position at least a portion of the light representing the line ahead of an imaging field of view in a scan direction;
- adjust, using the at least a portion of the line ahead of the imaging field of view in the scan direction, a focus of the inspection system based on data from the position sensing device;
- and
- adjust a position of the optical element to reposition the line when a scan direction changes.
A method for focus tracking in an inspection system that improves focus information and adjusts positions in a scan, the method comprising:
- projecting light representing a line onto a surface of an article under inspection;
- positioning at least a portion of the light representing the line ahead of an imaging field of view in a scan direction;
- adjusting, using reflected light from the at least a portion of the line ahead of the imaging field of view in the scan direction, a focus of the inspection system;
- and
- adjusting a position of an optical element to reposition the line when a scan direction changes.
An inspection system comprising:
- a microscope having a lens with an imaging field of view for capturing images of a surface of an article under inspection;
- and
- a focus tracking system including:
- an optical displacement sensor configured to generate light in the form of a line;
- an optical element configured to project the line onto a surface of an article under inspection;
- a position sensing device configured to detect light representing a reflected line from the surface of the article under inspection;
- and
- a controller configured to:
- position at least a portion of the light representing the line ahead of an imaging field of view in a scan direction;
- adjust, using the at least a portion of the line ahead of the imaging field of view in the scan direction, a focus of the inspection system based on data from the position sensing device;
- and
- adjust a position of the optical element to reposition the line when a scan direction changes.
Dependencies are inferred from the claim text.