Process window analysis

• US 10,720,367 B2
• Filed: 06/03/2019
• Issued: 07/21/2020
• Est. Priority Date: 03/23/2015
• Status: Active Grant

• Current Assignee: Applied Materials Israel Limited (Applied Materials Incorporated)
• Original Assignee: Applied Materials Israel Limited (Applied Materials Incorporated)
• Inventors: Kaizerman, Idan, Sofer, Yotam
• Primary Examiner(s): Tran, Dzung
• Application Number:
  US16/429,533
• Publication Number:
  US 20190355628A1
• Time in Patent Office: 414 Days
• Field of Search: 702 81
• CPC Class Codes: G03F 7/70558 Dose control, i.e. achievement of a desired dose
• CPC Class Codes: G03F 7/70641 Focus
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G03F 7/70655 Non-optical, e.g. atomic force microscope [AFM] or critical dimension scanning electron microscope [CD-SEM]
• CPC Class Codes: G03F 7/706833 Sampling plan selection or optimisation, e.g. select or optimise the number, order or locations of measurements taken per die, workpiece, lot or batch
• CPC Class Codes: H01J 2237/221 Image processing
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 2237/30416 Handling of data for lithography H01J37/3174
• CPC Class Codes: H01J 2237/30433 System calibration for microscopes H01J2237/2826
• CPC Class Codes: H01J 2237/30461 pre-calculated
• CPC Class Codes: H01J 2237/31798 detecting pattern defects with SEM H01J2237/2817; correcting H01J2237/31735, H01J2237/3174
• CPC Class Codes: H01J 37/222 Image processing arrangements associated with the tube image data processing or generation, in general G06T
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01J 37/304 Controlling tubes by information coming from the objects or from the beam, e.g. correction signals
• CPC Class Codes: H01J 37/3174 Particle-beam lithography, e.g. electron beam lithography
• 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 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A method for process analysis includes acquiring first inspection data, using a first inspection modality, with respect to a substrate having multiple instances of a predefined pattern of features formed thereon using different, respective sets of process parameters. Characteristics of defects identified in the first inspection data are processed so as to select a first set of defect locations in which the first inspection data are indicative of an influence of the process parameters on the defects. Second inspection data are acquired, using a second inspection modality having a finer resolution than the first inspection modality, of the substrate at the locations in the first set. The defects appearing in the second inspection data are analyzed so as to select, from within the first set of the locations, a second set of the locations in which the second inspection data are indicative of an optimal range of the process parameters.

Claims

1. A method comprising:

acquiring, by a processor, inspection data collected by using an inspection modality during an inspection process of a substrate having instances of a pattern, each of the instances of the pattern being formed by a fabrication process utilizing different respective sets of process parameters associated with the fabrication process of the substrate;

identifying, by the processor, defects at locations in the instances of the pattern based on the inspection data;

analyzing, by the processor, characteristics of the identified defects to select a portion of the locations at which the inspection data is indicative of an influence of the process parameters associated with the fabrication process on the identified defects;

determining a range of the process parameters associated with the fabrication process on the identified defects based on the portion of the locations at which the inspection data is indicative of the influence of the process parameters on the identified defects; and

determining subsequent process parameters for fabrication of a target device based on the range of the process parameters.

2. The method of claim 1, wherein the different respective sets of the process parameters correspond to lithographic parameters of a lithographic process.

3. The method of claim 2, wherein the lithographic parameters include a focal adjustment and an exposure level used for lithographic patterning of the lithographic process.

4. The method of claim 1, wherein analyzing the characteristics of the identified defects to select the portion of the locations at which the inspection data is indicative of the influence of the process parameters associated with the fabrication process on the identified defects comprises:

assigning the identified defects to groups of defects; and

determining whether the inspection data is indicative of the influence of the process parameters based on respective defects assigned to a respective group of the groups of defects changing in appearance in the instances of the pattern and a change to the process parameters on the identified defects of the respect group.

5. The method of claim 1, wherein the inspection modality is an optical imaging modality.

6. The method of claim 1, wherein analyzing the characteristics of the identified defects is based on a second inspection modality that is different than the inspection modality.

7. The method of claim 1, wherein analyzing the characteristics of the identified defects to select the portion of the locations at which the inspection data is indicative of the influence of the process parameters is based on a utility function.

8. A system comprising:

a memory; and

a processor, operatively coupled with the memory, to;

acquire inspection data collected by using an inspection modality during an inspection process of a substrate having instances of a pattern, each of the instances of the pattern being formed by a fabrication process utilizing different respective sets of process parameters associated with the fabrication process of the substrate;

identify defects at locations in the instances of the pattern based on the inspection data;

analyze characteristics of the identified defects to select a portion of the locations at which the inspection data is indicative of an influence of the process parameters associated with the fabrication process on the identified defects;

determine a range of the process parameters associated with the fabrication process on the identified defects based on the portion of the locations at which the inspection data is indicative of the influence of the process parameters on the identified defects; and

determine subsequent process parameters for fabrication of a target device based on the range of the process parameters.

9. The system of claim 8, wherein the different respective sets of the process parameters correspond to lithographic parameters of a lithographic process.

10. The system of claim 9, wherein the lithographic parameters include a focal adjustment and an exposure level used for lithographic patterning of the lithographic process.

11. The system of claim 8, wherein to analyze the characteristics of the identified defects to select the portion of the locations at which the inspection data is indicative of the influence of the process parameters associated with the fabrication process on the identified defects, the processor is further to:

assign the identified defects to groups of defects; and

determine whether the inspection data is indicative of the influence of the process parameters based on respective defects assigned to a respective group of the groups of defects changing in appearance in the instances of the pattern and a change to the process parameters on the identified defects of the respect group.

12. The system of claim 8, wherein the inspection modality is an optical imaging modality.

13. The system of claim 8, wherein analyzing the characteristics of the identified defects is based on a second inspection modality that is different than the inspection modality.

14. The system of claim 8, wherein analyzing the characteristics of the identified defects to select the portion of the locations at which the inspection data is indicative of the influence of the process parameters is based on a utility function.

15. A non-transitory computer readable medium comprising instructions, which when executed by a processor, cause the processor to perform operations comprising:

acquiring, by the processor, inspection data collected by using an inspection modality during an inspection process of a substrate having instances of a pattern, each of the instances of the pattern being formed by a fabrication process utilizing different respective sets of process parameters associated with the fabrication process of the substrate;

identifying, by the processor, defects at locations in the instances of the pattern based on the inspection data;

analyzing, by the processor, characteristics of the identified defects to select a portion of the locations at which the inspection data is indicative of an influence of the process parameters associated with the fabrication process on the identified defects;

determining a range of the process parameters associated with the fabrication process on the identified defects based on the portion of the locations at which the inspection data is indicative of the influence of the process parameters on the identified defects; and

determining subsequent process parameters for fabrication of a target device based on the range of the process parameters.

16. The non-transitory computer readable medium of claim 15, wherein the different respective sets of the process parameters correspond to lithographic parameters of a lithographic process.

17. The non-transitory computer readable medium of claim 16, wherein the lithographic parameters include a focal adjustment and an exposure level used for lithographic patterning of the lithographic process.

18. The non-transitory computer readable medium of claim 15, wherein the analyzing of the characteristics of the identified defects to select the portion of the locations at which the inspection data is indicative of the influence of the process parameters associated with the fabrication process on the identified defects comprises:

assigning the identified defects to groups of defects; and

determining whether the inspection data is indicative of the influence of the process parameters based on respective defects assigned to a respective group of the groups of defects changing in appearance in the instances of the pattern and a change to the process parameters on the identified defects of the respect group.

19. The non-transitory computer readable medium of claim 15, wherein the inspection modality is an optical imaging modality.

20. The non-transitory computer readable medium of claim 15, wherein the analyzing of the characteristics of the identified defects is based on a second inspection modality that is different than the inspection modality.