Apparatus for measuring overlay errors

A metrology system for determining the overlay between at least two separately generated patterns on a single or successive layers of a substrate, the system comprising:

• an optical assembly for capturing images of an overlay mark comprising:
• a first set of working zones being formed from a first process and having at least two working zones that are diagonally opposed and spatially offset relative to each other, each of the first set of working zones including a periodic structure comprising a plurality of coarsely segmented elements that are each formed from a plurality of finely segmented elements that are evenly divided over the entire coarsely segmented elements of the first set of working zones, and
• a second set of working zones being formed from a second process and having at least two working zones that are diagonally opposed and spatially offset relative to each other, each of the second set of working zones including a periodic structure comprising a plurality of coarsely segmented elements that are each formed from a plurality of finely segmented elements that are evenly divided over the entire coarsely segmented elements of the second set of working zones;
• and
• a computer for analyzing the captured images to determine whether the overlay mark has an overlay error.

A metrology system for determining the overlay between at least two separately generated patterns on a single or successive layers of a substrate, the system comprising:

• an optical assembly for capturing images of a multidirectional overlay mark comprising:
• a plurality of first periodic structures formed via a first process and having a first orientation and comprised of a plurality of coarsely segmented elements, wherein the first periodic structures comprise at least two working zones that are diagonally opposed and spatially offset relative to each other;
• a plurality of second periodic structures formed via a second process and having the first orientation and comprised of a plurality of coarsely segmented elements, wherein the second periodic structures comprise at least two working zones that are diagonally opposed and spatially offset relative to each other;
• a plurality of third periodic structures formed via the first process and having a second orientation and comprised of a plurality of coarsely segmented elements, wherein the third periodic structures comprise at least two working zones that are diagonally opposed and spatially offset relative to each other;
• and
• a plurality of fourth periodic structures formed via the second process and having the second orientation and comprised of a plurality of coarsely segmented elements, wherein the fourth periodic structures comprise at least two working zones that are diagonally opposed and spatially offset relative to each other,
• wherein each of the working zones of the first plurality of periodic structures is adjacent to one of the working zones of the second plurality of periodic structures, and
• wherein each of the working zones of the third plurality of periodic structures is adjacent to one of the working zones of the fourth plurality of periodic structures;
• and
• a computer for analyzing the captured images to determine whether the multidirectional overlay mark has an overlay error.

A metrology system for determining the overlay between at least two separately generated patterns on a single or successive layers of a substrate, the system comprising:

• an optical assembly for capturing images of a multidirectional overlay mark comprising:
• a first set of working zones being formed from a first process, and each first set of working zones including a periodic structure of a plurality of elements that are spaced apart within a plurality of lines and configured to convey overlay information in a first direction and a second direction that differs from the first direction;
• and
• a second set of working zones being formed from a second process, and each second set of working zones including a periodic structure of a plurality of elements that are spaced apart within a plurality of lines and configured to convey overlay information in the first direction and the second direction,
• wherein the first set, of working zones and second set of working zones are diagonally opposed and spatially offset relative to one another, and
• wherein the elements are substantially distributed over an area of the overlay mark;
• and
• a computer for analyzing the captured images to determine whether the multidirectional overlay mark has an overlay error.

A metrology system for determining the overlay between at least two separately generated patterns on a single or successive layers of a substrate, the system comprising:

• an optical assembly for capturing images of a multidirectional overlay mark comprising:
• a first quadrant having only two separately generated working zones, that are juxtaposed relative to one another, and are configured to provide overlay information in a first direction, and each include a periodic structure comprised of a plurality of coarsely segmented elements positioned therein, and that together substantially fill their quadrant,
• a second quadrant having only two separately generated working zones, that are juxtaposed relative to one another, and are configured to provide overlay information in the first direction, and each include a periodic structure comprised of a plurality of coarsely segmented elements positioned therein, and that together substantially fill their quadrant,
• a third quadrant having only two separately generated working zones, that are juxtaposed relative to one another, and are configured to provide overlay information in a second direction that differs from the first direction, and each include a periodic structure comprised of a plurality of coarsely segmented elements positioned therein, and that together substantially fill their quadrant, and
• a fourth quadrant having only two separately generated working zones, that are juxtaposed relative to one another, and are configured to provide overlay information in the second direction, and each include a periodic structure comprised of a plurality of coarsely segmented elements positioned therein, and that together substantially fill their quadrant,
• wherein each quadrant includes an inner working zone and an outer working zone, the inner working zone being positioned towards the center of the multidirectional overlay mark, the outer working zone being positioned toward the periphery of the multidirectional overlay mark,
• wherein the coarsely segmented elements are finely segmented in order to control the contrast of the resultant image in the metrology system;
• and
• a computer for analyzing the captured images to determine whether the multidirectional mark has an overlay error.