Layout for reticle and wafer scanning electron microscope registration or overlay measurements

Abstract

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.

What is claimed is: 
     
         1 . A method comprising:
 forming an initial metal monitoring structure having a first portion having first and second edges separated by a first distance in a first direction, the initial metal monitoring structure being formed in an initial metal layer of a semiconductor substrate;   forming a subsequent metal monitoring structure having a first portion having first and second edges separated by a second distance in the first direction, the subsequent metal monitoring structure being formed in a subsequent metal layer adjoining the initial metal layer; and   forming one or more vias within the first portion of the subsequent metal monitoring structure, the via exposing the first and second edges of the first portion of the initial metal monitoring structure,   wherein the initial and the subsequent monitoring structures are formed in an area which includes no integrated circuit (IC) patterns in the initial metal layer and the subsequent metal layer, respectively, the one or more vias comprise at least first, second, and third vias, the first and second vias expose the first and second edges of the initial metal monitoring structure, and the second and third vias expose the first and second edges of the subsequent monitoring structure.   
     
     
         2 . The method according to  claim 1 , comprising forming each of the initial metal monitoring structure and the subsequent metal monitoring structure having a second portion, wherein a part of the second portion of the subsequent metal monitoring structure overlays a part of the second portion of the initial metal monitoring structure. 
     
     
         3 . The method according to  claim 2 , wherein the first and second portions of the initial metal monitoring structure extend perpendicular to the first and second portions of the subsequent metal monitoring structure, respectively. 
     
     
         4 . The method according to  claim 1 , comprising forming each of the initial and the subsequent metal monitoring structures in a cross shape by:
 forming the initial metal monitoring structure having:   a second portion having third and fourth edges separated by a third distance in a second direction,   a third portion having fifth and sixth edges separated by a fourth distance in the first direction, and   a fourth portion having seventh and eighth edges separated by a fifth distance in the second direction; and   forming the subsequent metal monitoring structure having:   a second portion having third and fourth edges separated by a sixth distance in the second direction, the sixth distance being greater than the third distance,   a third portion having fifth and sixth edges separated by a seventh distance in the first direction, the seventh distance being less than the fourth distance, and   a fourth portion having seventh and eighth edges separated by an eighth distance in the second direction, the eighth distance being less than the fifth distance.   
     
     
         5 . The method according to  claim 4 , comprising forming a second via within the second portion of the subsequent metal monitoring structure, exposing the third and fourth edges of the second portion of the initial metal monitoring structure. 
     
     
         6 . A device comprising:
 a semiconductor substrate;   an initial metal layer including an initial metal monitoring structure having a first portion having first and second edges separated by a first distance in a first direction;   a subsequent metal layer, adjoining the initial metal layer and including a subsequent metal monitoring structure having a first portion having first and second edges separated by a second distance in the first direction; and   a via through the subsequent metal monitoring structure and within the first portion of the subsequent metal monitoring structure, the via exposing the first and second edges of the first portion of the initial metal monitoring structure, wherein the initial metal monitoring structure and the subsequent metal monitoring structure are in an area which includes no IC pattern in the one or more initial metal layers and the one or more subsequent metal layers, respectively.   
     
     
         7 . The device according to  claim 6 , wherein each of the initial metal monitoring structure and the subsequent monitoring structure has a second portion, wherein a part of the second portion of the subsequent metal monitoring structure overlays a part of the second portion of the initial metal monitoring structure. 
     
     
         8 . The device according to  claim 7 , wherein the first and second portions of the initial metal monitoring structure extend perpendicular to the first and second portions of the subsequent metal monitoring structure, respectively. 
     
     
         9 . The device according to  claim 6 , wherein
 each of the initial and the subsequent metal monitoring structures is formed in a cross shape wherein:   the initial metal monitoring structure has:   a second portion having third and fourth edges separated by a third distance in a second direction,   a third portion having fifth and sixth edges separated by a fourth distance in the first direction, and   a fourth portion having seventh and eighth edges separated by a fifth distance in the second direction; and   the subsequent metal monitoring structure has:   a second portion having third and fourth edges separated by a sixth distance in the second direction, the sixth distance being greater than the third distance,   a third portion having fifth and sixth edges separated by a seventh distance in the first direction, the seventh distance being less than the fourth distance, and   a fourth portion having seventh and eighth edges separated by an eighth distance in the second direction, the eighth distance being less than the fifth distance.   
     
     
         10 . The device according to  claim 9 , further comprising a second via within the second portion of the subsequent metal monitoring structure, exposing the third and fourth edges of the second portion of the initial metal monitoring structure. 
     
     
         11 . A device comprising:
 a semiconductor substrate;   an initial layer including an initial metal monitoring structure having first and second edges separated by a first distance;   a subsequent layer including a subsequent metal monitoring structure having first and second edges separated by a second distance; and   a via layer including first, second, and third vias, collectively exposing at least the first and second edges of each of the initial metal monitoring structure and subsequent metal monitoring structures,   wherein the initial metal monitoring structure, the subsequent metal monitoring structure, and the first, second, and third vias are in an area which includes no IC pattern in the initial, the subsequent, and the via layers, respectively, and   wherein the first and second vias expose the first and second edges of the initial metal monitoring structure and the second and third vias expose the first and second edges of the subsequent metal monitoring structure.   
     
     
         12 . The device according to  claim 11 , further comprising:
 the initial metal monitoring structure having first and second edges separated by the first distance in a first direction; and   the subsequent metal monitoring structure having first and second edges separated by the second distance in a second direction that is different than the first direction.   
     
     
         13 . The device according to  claim 11 , further comprising:
 a second initial metal monitoring structure in the initial layer on a semiconductor substrate; and   a second subsequent metal monitoring structure in the subsequent layer,   wherein one of the first, second, and third vias exposes one of the first and second edges of each of the first initial metal monitoring structures and first subsequent metal monitoring structures and exposes a first edge of each of the second initial metal monitoring structures and second subsequent metal monitoring structures.   
     
     
         14 . The device according to  claim 12 , further comprising:
 a fourth via in the via layer, exposing a second edge of the second initial metal monitoring structure, opposite the first edge; and   a fifth via in the via layer, exposing a second edge of the second subsequent metal monitoring structure, opposite the first edge.   
     
     
         15 . The device according to  claim 11 , 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 initial metal monitoring structure or the subsequent metal monitoring structure and the first, second, third, and fourth edges are all exposed.   
     
     
         16 . The device according to  claim 11 , wherein the second distance is less than and in the same direction as the first distance;
 the initial metal monitoring structure has third and fourth edges separated by a third distance in a third direction different than the first direction;   the subsequent metal 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 via exposes the first, second, third, and fourth edges of the initial metal monitoring structure and first, second, third, and fourth edges of the subsequent metal monitoring structure.