Metrology system utilizing scan lens for points-from-focus type processes

A method for operating a metrology system,

• the metrology system comprising:
• a lighting configuration;
• a camera configured to receive image light transmitted along an imaging optical path and to provide images of a workpiece that is illuminated by the lighting configuration;
• a scan lens that is included in the imaging optical path and is configured to input image light arising from the workpiece as illuminated by the lighting configuration;
• a mirror configuration that is included in the imaging optical path and is configured to direct image light from the scan lens along the imaging optical path, wherein the mirror configuration comprises one or more mirrors that are configured to be adjusted to adjust an imaged field of view as corresponding to a view position through the scan lens;
• and
• a variable focal length (“VFL”) lens that is included in the imaging optical path, wherein image light travels from the mirror configuration along the imaging optical path and through the VFL lens to the camera, and the VFL lens is configured to be controlled to vary an optical power of the VFL lens so as to vary a focus position of the metrology system;
• the method comprising
• controlling the lighting configuration to provide light for illuminating the workpiece;
• utilizing the camera to acquire a first image set comprising a first plurality of images of the workpiece in accordance with a first imaged field of view as corresponding to a first view position through the scan lens, wherein the VFL lens is controlled to vary the focus position of the metrology system for acquiring the images of the first image set;
• utilizing the mirror configuration to adjust to a second imaged field of view as corresponding to a second view position through the scan lens;
• and
• utilizing the camera to acquire a second image set comprising a second plurality of images of the workpiece in accordance with the second imaged field of view as corresponding to the second view position through the scan lens, wherein the VFL lens is controlled to vary the focus position of the metrology system for acquiring the images of the second image set.

A metrology system, comprising:

• a lighting configuration;
• a camera configured to receive image light transmitted along an imaging optical path and to provide images of a workpiece that is illuminated by the lighting configuration;
• a scan lens that is included in the imaging optical path and is configured to input image light arising from the workpiece as illuminated by the lighting configuration;
• a mirror configuration that is included in the imaging optical path and is configured to direct image light from the scan lens along the imaging optical path, wherein the mirror configuration comprises one or more mirrors that are configured to be adjusted to adjust an imaged field of view as corresponding to a view position through the scan lens;
• and
• a variable focal length (“VFL”) lens that is included in the imaging optical path, wherein image light travels from the mirror configuration along the imaging optical path and through the VFL lens to the camera, and the VFL lens is configured to be controlled to vary an optical power of the VFL lens so as to vary a focus position of the metrology system;
• wherein the metrology system is configured to:
• control the lighting configuration to provide light for illuminating the workpiece;
• utilize the camera to acquire a first image set comprising a first plurality of images of the workpiece in accordance with a first imaged field of view as corresponding to a first view position through the scan lens, wherein the VFL lens is controlled to vary the focus position of the metrology system for acquiring the images of the first image set;
• utilize the mirror configuration to adjust to a second imaged field of view as corresponding to a second view position through the scan lens;
• and
• utilize the camera to acquire a second image set comprising a second plurality of images of the workpiece in accordance with the second imaged field of view as corresponding to the second view position through the scan lens, wherein the VFL lens is controlled to vary the focus position of the metrology system for acquiring the images of the second image set.