Detection device, detection method, lithography apparatus, and article manufacturing method

A detection device for detecting a relative position between a first mark provided on a first object and a second mark provided on a second object, which are arranged to be superimposed, wherein a third mark is provided on the first object and a fourth mark is provided on the second object, the detection device comprising:

• an illumination system configured to illuminate the first mark, the second mark, third mark, and the fourth mark with first illumination light;
• a first detection system including a first image sensor and a first aperture stop, and configured to form images of diffracted lights from the first mark and the second mark illuminated with the first illumination light by the illumination system on an imaging surface of the first image sensor via the first aperture stop;
• a second detection system including a second image sensor and a second aperture stop, wherein
• the second detection system forms images of lights from the third mark and the fourth mark illuminated with the second illumination light by the illumination system on an imaging surface of the second image sensor via the second aperture stop,
• wherein the first illumination light forms a first light intensity distribution asymmetric with respect to an optical axis of the illumination system on a pupil surface of the illumination system, or the first aperture stop is asymmetric with respect to an optical axis of the first detection system, and
• wherein the second illumination light forms a second light intensity distribution on the pupil surface of the illumination system, asymmetry of the second light intensity distribution with respect to the optical axis is different from asymmetry of the first light intensity distribution with respect to the optical axis, or asymmetry of the second aperture stop with respect to the optical axis of the second detection system is different from asymmetry of the first aperture stop with respect to the optical axis of the first detection system;
• and
• a processor configured to:
• determine an index value having correlation with defocus amounts of the first mark and the second mark in the first detection system based on a center-of-gravity position of the images of the first mark and the second mark captured by the first image sensor and a center-of-gravity position of the images of the third mark and the fourth mark captured by the second image sensor;
• and
• obtain the relative position between the first mark and the second mark based on an output of the first image sensor and the determined index value.

A detection method for detecting a relative position between a first mark provided on a first object and a second mark provided on a second object, which are arranged to be superimposed, the detection method comprising:

• while illuminating the first mark and the second mark with illumination light from an illumination system, forming, by a detection system including an image sensor and an aperture stop, images of diffracted lights from the first mark and the second mark illuminated with the illumination light on an imaging surface of the image sensor via the aperture stop;
• and
• wherein the illumination light forms a light intensity distribution asymmetric with respect to an optical axis of the illumination system on a pupil surface of the illumination system, or the aperture stop is asymmetric with respect to an optical axis of the detection system;
• and
• obtaining an index value having correlation with defocus amounts of the first mark and the second mark in the detection system;
• and
• obtaining the relative position between the first mark and the second mark by correcting relative position information between the first mark and the second mark obtained from the images of the first mark and the second mark captured by the first image sensor, using a correction value corresponding to the obtained index value.