Layout for reticle and wafer scanning electron microscope registration or overlay measurements
View Patent ↗A method and a resulting device are provided for forming stack overlay and registration monitoring structures for FEOL layers including implant layers and for forming BEOL SEM overlay and registration monitoring structures including BEOL interconnections, respectively. Embodiments include forming an active monitoring structure having first and second edges separated by a first distance in an active layer on a semiconductor substrate; forming a poly monitoring structure having first and second edges separated by a second distance in a poly layer; and forming one or more contact monitoring structures in a contact layer, collectively exposing at least the first and second edges of each of the active and poly monitoring structures; wherein the active, poly, and contact monitoring structures are formed in an area which includes no IC patterns in the active, the poly, and the contact layers, respectively.
1. A method comprising:
forming an active monitoring structure having first and second edges separated by a first distance in an active layer on a semiconductor substrate;
forming a polysilicon (poly) monitoring structure having first and second edges separated by a second distance in a poly layer; and
forming one or more contact monitoring structures in a contact layer, collectively exposing at least the first and second edges of each of the active and poly monitoring structures;
wherein the active, poly, and contact monitoring structures are formed in an area which includes no integrated circuit (IC) patterns in the active, the poly, and the contact layers, respectively, the one or more contact monitoring structures comprise at least first, second, and third contact monitoring structures, the first and second contact monitoring structures expose the first and second edges of the active monitoring structure, and the second and third contact monitoring structures expose the first and second edges of the poly monitoring structure.
2. The method according to claim 1 , wherein:
the first and second distances are in different directions.
3. The method according to claim 1 , further comprising:
forming a second active monitoring structure in the active layer on a semiconductor substrate; and
forming a second poly monitoring structure in the poly layer,
wherein one of the first, second, and third contact monitoring structures exposes one of the first and second edges of each of the first active and first poly monitoring structures and exposes a first edge of each of the second active and second poly monitoring structures.
4. The method according to claim 3 , further comprising:
forming a fourth contact monitoring structure in the contact layer, exposing a second edge of the second active monitoring structure, opposite the first edge; and
forming a fifth contact monitoring structure in the contact layer, exposing a second edge of the second poly monitoring structure, opposite the first edge.
5. The method according to claim 1 , further comprising:
forming a plurality of implant monitoring structures in an implant layer on the semiconductor substrate in an area which includes no IC patterns in the implant layer,
wherein a first implant monitoring structure having first, second, third, and fourth edges is formed on top of either the active monitoring structure or the poly monitoring structure, and the first, second, third, and fourth edges are all exposed.
6. The method according to claim 1 , wherein:
the second distance is less than and in the same direction as the first distance;
the active monitoring structure has third and fourth edges separated by a third distance in a third direction different than the first direction;
the poly monitoring structure has third and fourth edges separated by a fourth distance less than and in the same direction as the third distance; and
one contact monitoring structure exposes the first, second, third, and fourth edges of the active monitoring structure and first, second, third, and fourth edges of the poly monitoring structure.
7. A device comprising:
a semiconductor substrate;
an active layer including an active monitoring structure having first and second edges separated by a first distance;
a poly layer including a poly monitoring structure having first and second edges separated by a second distance; and
a contact layer including first, second, and third contact monitoring structures, collectively exposing at least the first and second edges of each of the active and poly monitoring structures,
wherein the active monitoring structures, the poly monitoring structure, and the first, second, and third contact monitoring structures are in an area which includes no IC pattern in the active, the poly, and the contact layers, respectively, and
wherein the first and second contact monitoring structures expose the first and second edges of the active monitoring structure and the second and third contact monitoring structures expose the first and second edges of the poly monitoring structure.
8. The device according to claim 7 , further comprising:
the active monitoring structure having first and second edges separated by the first distance in a first direction; and
the poly monitoring structure having first and second edges separated by the second distance in a second direction that is different than the first direction.
9. The device according to claim 7 , further comprising:
a second active monitoring structure in the active layer on a semiconductor substrate; and
a second poly monitoring structure in the poly layer,
wherein one of the first, second, and third contact monitoring structures exposes one of the first and second edges of each of the first active and first poly monitoring structures and exposes a first edge of each of the second active and second poly monitoring structures.
10. The device according to claim 9 , further comprising:
a fourth contact monitoring structure in the contact layer, exposing a second edge of the second active monitoring structure, opposite the first edge; and
a fifth contact monitoring structure in the contact layer, exposing a second edge of the second poly monitoring structure, opposite the first edge.
11. The device according to claim 7 , further comprising:
a plurality of implant monitoring structures in an implant layer on the semiconductor substrate in an area which includes no IC patterns in the implant layer,
wherein a first implant monitoring structure having first, second, third, and fourth edges is formed on top of either the active monitoring structure or the poly monitoring structure and the first, second, third, and fourth edges are all exposed.
12. The device according to claim 7 , wherein the second distance is less than and in the same direction as the first distance;
the active monitoring structure has third and fourth edges separated by a third distance in a third direction different than the first direction;
the poly monitoring structure has third and fourth edges separated by a fourth distance less than and in the same direction as the third distance; and
one contact monitoring structure exposes the first, second, third, and fourth edges of the active monitoring structure and first, second, third, and fourth edges of the poly monitoring structure.