Test structure design for metrology measurements in patterned samples

Patent metadata

Field	Value
Publication number	US-11639901-B2
Application number	US-202117498013-A
Country	US
Kind code	B2
Filing date	Oct 11, 2021
Priority date	Jun 19, 2014
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

A test structure for use in metrology measurements of a sample pattern formed by periodicity of unit cells, each formed of pattern features arranged in a spaced-apart relationship along a pattern axis, the test structure having a test pattern, which is formed by a main pattern which includes main pattern features of one or more of the unit cells and has a symmetry plane, and a predetermined auxiliary pattern including at least two spaced apart auxiliary features located within at least some of those features of the main pattern, parameters of which are to be controlled during metrology measurements.

First claim

What is claimed is:

1. A test structure for use in metrology measurements of a sample pattern formed by a periodicity of unit cells, where each of the unit cells is formed of pattern features arranged in a spaced-apart relationship along a pattern axis, the test structure comprising a test pattern formed by a main pattern formed by two or more layers which includes main pattern features and has a symmetry plane, and a predetermined auxiliary pattern including at least two spaced-apart auxiliary features located within at least a part of the main pattern, wherein parameters of the main pattern are to be controlled during metrology measurements, and wherein the auxiliary features of the auxiliary pattern are configured and arranged with respect to the main pattern such that misalignment of said two or more layers breaks a condition of symmetry around the symmetry plane causing a deviation in an optical response from the test structure.

2. The test structure according to claim 1 wherein said main pattern is formed by a stack of said two or more layers.

3. The test structure according to claim 1 wherein the test structure is adapted for use in performing any of overlay measurements, double-patterning, multi-patterning, Spacer Assisted Double Patterning (SADP), Self-Aligned Triple Patterning (SATP), and Litho-Etch-Litho-Etch (LELE) techniques.

4. The test structure according to claim 1 wherein the main pattern includes lines.

5. The test structure according to claim 1 , wherein two vias are located at opposite sides of a line between said two spaced-apart auxiliary features and at opposite ends of said line.

6. The test structure according to claim 1 wherein the auxiliary pattern is in the form of a surface relief formed by features arranged in a spaced-apart relationship and being located within at least some of the features of the main pattern.

7. The test structure according to claim 6 wherein the surface relief features are any of grooves and vias.

8. The test structure according to claim 1 , wherein data indicative of the optical response comprises a relation between first and second measured data pieces corresponding to first and second measurements taken at different measurement conditions.

9. The test structure according to claim 8 , wherein said relation is a difference between the first and second measured data pieces.

10. The test structure according to claim 8 , wherein said different measurement conditions are characterized by different polarizations of light collected from the test structure.

11. A method for use in metrology measurements of patterned samples, the method comprising: associating the patterned sample being measured with a corresponding test structure configured according to claim 1 ;
performing at least one measurement session on said test structure using a measurement plane parallel to the symmetry plane of the main pattern in the test structure, the measurement session comprising at least first and second measurements, each directing illuminating light onto said test structure along an illumination channel and collecting light reflected from said test structure propagating along a collection channel to be detected, such that detected light has a polarization state different from polarization of the illuminating light, and generating a measured data piece indicative of the light detected in the measurement, thereby generating at least first and second measured data pieces for said at least first and second measurements on the same test structure corresponding to the detected light having different first and second polarization states; and
determining a relation between said at least first and second measured data pieces indicative of parameters of said main features in the main pattern.

Assignees

• Nova Ltd

Inventors

• Barak Gilad
• Cohen Oded
• Turovets Igor

Classifications

• H10P74/27

  Structural arrangements therefor · CPC title

• G01N21/9501

  Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20) · CPC title

• G01B2210/56

  Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth · CPC title

• G01N21/956 Primary

  Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} · CPC title

• G01N21/8806

  Specially adapted optical and illumination features · CPC title