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US 11,686,576 B2Granted
Metrology target for one-dimensional measurement of periodic misregistration
AssigneeKLA Corporation
InventorsYoel Feler, Mark Ghinovker
Life of this patent
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Abstract
A metrology target includes a first target structure set having one or more first target structures formed within at least one of a first working zone or a second working zone of a sample. The metrology target includes a second target structure set having one or more second target structures formed within at least one of the first working zone or the second working zone. The first working zone may include a center of symmetry that overlaps with a center of symmetry of the second working zone when an overlay error of one or more layers of the sample is not present. The metrology target may additionally include a third target structure set, a fourth target structure set, or a fifth target structure set.
Claims46
A metrology target, comprising:
- a first target structure set formed on a sample, wherein the first target structure set comprises a first set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the at least the second working zone, wherein the first target structure set includes periodic structures along one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the first set of working zones;
- and
- a second target structure set formed on the sample, wherein the second target structure set comprises at least a second set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the at least the second working zone, wherein the second target structure set includes periodic structures along the one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the at least the second set of working zones,
- wherein the first set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the first set of working zones and the at least the second set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the at least the second set of working zones,
- wherein a difference between the center of rotation symmetry of the first set of working zones and the center of rotation symmetry of the at least the second set of working zones is indicative of overlay error along the one measurement direction.
2 more elements
A system comprising:
- a controller communicatively couplable to one or more metrology sub-systems, wherein the controller includes one or more processors, wherein the one or more processors are configured to execute a set of program instructions maintained in memory, wherein the set of program instructions is configured to cause the one or more processors to:
- receive, from the one or more metrology sub-systems, one or more signals indicative of illumination emanating from a metrology target of a sample, wherein the metrology target of the sample comprises:
- a first target structure set formed on a sample, wherein the first target structure set comprises a first set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the at least the second working zone, wherein the first target structure set includes periodic structures along one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the first set of working zones;
- and a second target structure set formed on the sample, wherein the second target structure set comprises at least a second set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the second working zone, wherein the second target structure set includes periodic structures along the one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the at least the second set of working zones, wherein the first set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the first set of working zones and the at least the second set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the at least the second set of working zones, wherein a difference between the center of rotation symmetry of the first set of working zones and the center of rotation symmetry of the at least the second set of working zones;
- generate at least a first overlay measurement based on one or more signals indicative of illumination emanating from one or more portions of the first target structure set;
- generate at least a second overlay measurement based on one or more signals indicative of illumination emanating from one or more portions of the second target structure set;
- and
- determine an overlay error along the one measurement direction of the sample based on the first overlay measurement and the second overlay measurement.
5 more elements
A method of measuring overlay of a sample, comprising:
- illuminating a sample having a metrology target, the metrology target comprising:
- a first target structure set formed on a sample, wherein the first target structure set comprises a first set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the at least the second working zone, wherein the first target structure set includes periodic structures along one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the first set of working zones;
- and a second target structure set formed on the sample, wherein the second target structure set comprises at least a second set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the second working zone, wherein the second target structure set includes periodic structures along the one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the at least the second set of working zones, wherein the first set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the first set of working zones and the at least the second set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the at least the second set of working zones, wherein a difference between the center of rotation symmetry of the first set of working zones and the center of rotation symmetry of the at least the second set of working zones;
- detecting illumination emanating from the metrology target of the sample;
- generating at least a first overlay measurement based on one or more signals indicative of illumination emanating from one or more portions of the first target structure set;
- generating at least a second overlay measurement based on one or more signals indicative of illumination emanating from one or more portions of the second target structure set;
- and
- determining an overlay error along the one measurement direction of the sample based on the first overlay measurement and the second overlay measurement.
5 more elements
A method of forming a metrology target comprising:
- forming a first target structure set on a sample, wherein the first target structure set comprises a first set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the at least the second working zone, wherein the first target structure set includes periodic structures along one measurement direction, wherein an orientation of one or more patterns in the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the first set of working zones;
- and
- forming a second target structure set on the sample, wherein the second target structure set comprises at least a second set of working zones comprising a first working zone and at least a second working zone, wherein a first target structure is formed within the first working zone and at least a second target structure is formed within the second working zone, wherein the second target structure set includes periodic structures along the one measurement direction, wherein an orientation of one or more patterns of the first working zone of the first set of working zones is different from the orientation of one or more patterns in the at the second working zone of the first set of working zones, wherein the first set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the first set of working zones and the at least the second set of working zones is at least two-fold rotationally symmetric about a center of rotation symmetry of the at least the second set of working zones, wherein a difference between the center of rotation symmetry of the first set of working zones and the center of rotation symmetry of the at least the second set of working zones.
Dependencies are inferred from the claim text.