Device correlated metrology (DCM) for OVL with embedded SEM structure overlay targets

• US 9,093,458 B2
• Filed: 02/25/2013
• Issued: 07/28/2015
• Est. Priority Date: 09/06/2012
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Amir, Nuriel, Itzkovich, Tal, Kandel, Daniel, Choi, DongSub
• Primary Examiner(s): Garber, Charles
• Assistant Examiner(s): ISAAC, STANETTA D
• Application Number:
  US13/776,550
• Publication Number:
  US 20140065736A1
• Time in Patent Office: 883 Days
• Field of Search: 438/14, 257/797
• US Class Current: 1/1
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: G03F 7/70683 Mark designs
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Aspects of the present disclosure describe a target for use in measuring a relative position between two substantially coplanar layers of a device. The target includes periodic structures in first and second layers. Differences in relative position of the first and the second layers between the first and second periodic structures and the respective device-like structure can be measured to correct the relative position of the first and the second layers between the first and second periodic structures. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. A target for use in measuring a relative position between two substantially coplanar layers of a device, wherein a second layer of the two substantially coplanar layers is located on top of a first layer of the two substantially coplanar layers, the target comprising:

a first periodic structure formed in the first layer, wherein the first periodic structure includes one or more windows for viewing a structure in a layer under the first layer;

a first device-like structure formed in the first layer within the first periodic structure;

a second periodic structure formed in the second layer, wherein the second periodic structure includes one or more windows for viewing portions of the first periodic structure in the first layer; and

a second device-like structure formed in the second layer within the second periodic structure, wherein the first and second periodic structures and the first and second device-like structures are configured such that differences in relative position of the first and the second layers between the first and second periodic structures and differences between the first and second device-like structures can be measured.

2. The target of claim 1, wherein first and second device-like structures are configured such that differences in relative position of the first and the second device-like structures can be measured by a critical dimension scanning electron microscope (CD-SEM).

3. The target of claim 1, wherein the first device-like structure and the second device-like structure include elements that are about same size and pitch as device elements of an integrated circuit.

4. The target of claim 1, wherein a pitch in the first device-like structure and the second device-like structure is between about 5 nm and about 80 nm.

5. The target of claim 1, wherein a linewidth in the first device-like structure and the second device-like structure is between about 2 nm and about 40 nm.

7. The target of claim 1, wherein the first periodic structure and the second periodic structure is configured as an imaging overlay target or a scatterometry overlay target.

8. The target of claim 1, wherein the first periodic structure and the second periodic structure include elements for optical overlay measurements.

9. The target of claim 1, wherein the first periodic structure and the second periodic structure are configured as a scatterometry overlay target, wherein a pitch in the first periodic structure and the second periodic structure is between about 150 nm and about 1000 nm.

10. The target of claim 1, wherein the first periodic structure and the second periodic structure are configured as a scatterometry overlay target, wherein a linewidth and spacing in the first periodic structure and the second periodic structure is between about 50 nm and about 700 nm.

11. The target of claim 1, wherein the first periodic structure and the second periodic structure are configured as an imaging overlay target, wherein a pitch in the first periodic structure and the second periodic structure is between about 2 nm and about 40 nm.

12. The target of claim 1, wherein the first periodic structure and the second periodic structure are configured as an imaging overlay target for an AIM tool, wherein a pitch in the first periodic structure and the second periodic structure is more than 2.5 microns.

6. The target of claim l, wherein the first device-like structure and the second device-like structure are respectively located in the middle portion of the corresponding periodic structure.

13. A target for use in measuring a relative position between two substantially coplanar layer of a device, wherein a second layer of the two layers is located on top of a first layer of the two layer, the target comprising:

a first periodic structure formed in the first layer, wherein the first periodic structure includes one or more windows for viewing portions of a structure in a layer under the first layer;

a second periodic structure formed in the second layer, wherein the second periodic structure includes one or more windows for viewing portions of the first periodic structure in the first layer; and

wherein the first and second periodic structures are configured such that differences in the relative position of the first and the second layers between the first and second periodic structures can be measured.

14. The target of claim 13, wherein the first periodic structure and the second periodic structure include elements that are about same size and pitch as elements of an integrated circuit.

15. The target of claim 13, wherein the first and second periodic structures are configured such that differences in the relative position of the first and the second layers between the first and second periodic structures can be measured by a critical dimension scanning electron microscope (CD-SEM).

16. The target of claim 13, wherein the windows in the first periodic structure are configured to align with corresponding windows in the second periodic structure for use in measuring a relative position of the first layer and the second layer.

17. A method, comprising:

forming a first periodic structure in a first layer with one or more windows for viewing portions of a periodic structure in a layer under the first layer;

forming a first device-like structure in the first layer within the first periodic structure;

forming a second periodic structure in a second layer on top of the first layer, wherein the second periodic structure includes one or more windows for viewing portions the periodic structure in the first layer; and

forming a second device-like structure in the second layer within the second periodic structure,

wherein the first and second periodic structures are configured such that differences in the relative position of the first and the second layers between the first and second periodic structures can be measured.

18. The method of claim 17, further comprising measuring a shift between the first periodic structure and the first device-like structure and a shift between the second periodic structure and the second device-like structure.

19. The method of claim 17, further comprising measuring an overlay error with the first periodic structure and the second periodic structure after a developing step.

20. The method of claim 17, further comprising measuring an overlay error with the first periodic structure and the second periodic structure after an etch step.