Optical mode analysis with design-based care areas

• US 9,702,827 B1
• Filed: 11/19/2015
• Issued: 07/11/2017
• Est. Priority Date: 11/20/2014
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Brauer, Bjorn, Sanapala, Ravikumar
• Primary Examiner(s): Pham, Hoa
• Application Number:
  US14/946,604
• Time in Patent Office: 600 Days
• Field of Search: 3562371-2375, 250307, 250310, 250311
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 2201/11 Monitoring and controlling the scan

Abstract

Methods and systems for selecting one or more modes of an inspection subsystem or system for inspection of a specimen are provided. The systems described herein are configured to acquire output for all of the modes to be considered at a location of a known defect on the specimen by aligning output, which is generated at the location with a mode known to generate output in which patterned features on the specimen are resolved to a degree that allows the output to be aligned to design data, with the design data for the specimen to identify the location with substantially high accuracy and then without moving the field of view of the inspection subsystem or system from that location, acquiring the output for all other modes. All of the acquired output can then be used to select mode(s) for inspection of the specimen or another specimen of the same type.

Claims

1. A system configured to select one or more modes of an inspection subsystem for inspection of a specimen, comprising:

an inspection subsystem comprising at least an energy source, a detector, and a scanning subsystem, wherein the energy source is configured to generate energy that is directed to a specimen by the inspection subsystem, wherein the detector is configured to detect energy from the specimen and to generate output responsive to the detected energy, wherein the scanning subsystem is configured to change a position on the specimen to which the energy is directed and from which the energy is detected, and wherein the scanning subsystem comprises a mechanical assembly configured to move the specimen and a stage on which the specimen is disposed; and

a computer subsystem, wherein the computer subsystem is a device having one or more processors executing instructions from a memory medium, and wherein the computer subsystem is configured for;

a) setting values for one or more parameters of the inspection subsystem to a first mode known to generate output in which patterned features on the specimen are resolved to a degree that allows the output to be aligned to design data for the specimen;

b) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a first position on the specimen at which a first known defect is located;

c) acquiring the output generated by the detector at the first position with the first mode;

d) aligning the acquired output to the design data;

e) altering the values for the one or more parameters of the inspection subsystem to a second mode different than the first mode;

f) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the first position, acquiring the output generated by the detector at the first position with the second mode;

g) repeating steps e) and f) for one or more additional modes of the inspection subsystem;

h) setting the values for the one or more parameters of the inspection subsystem to the first mode;

i) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a second position on the specimen at which a reference for the first position is formed;

j) acquiring the output generated by the detector at the second position with the first mode;

k) altering the values for the one or more parameters of the inspection subsystem to the second mode;

l) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the second position, acquiring the output generated by the detector at the second position with the second mode;

m) repeating steps k) and l) for the one or more additional modes of the inspection subsystem;

n) repeating steps a) through g) for one or more additional positions on the specimen at which one or more additional known defects are located;

o) repeating steps h) through m) for one or more further positions on the specimen at which one or more references for the one or more additional positions are formed; and

p) selecting one or more modes of the inspection subsystem for inspection of the specimen or another specimen of the same type as the specimen based on all of the output generated by all of the steps performed by the computer subsystem.

2. The system of claim 1, wherein the first position is located within a first design-based care area, and wherein the one or more additional positions are located within other design-based care areas different than the first.

3. The system of claim 1, wherein aligning the acquired output to the design data comprises overlaying a portion of the design data with the acquired output or an image generated from the acquired output.

4. The system of claim 1, wherein at least one of the first known defect and the one or more additional known defects is located at an edge of a memory area of a device being formed on the specimen.

5. The system of claim 1, wherein the first known defect and the reference for the first position are located in different cells in a memory area of a device being formed on the specimen.

6. The system of claim 1, wherein the first known defect and the reference for the first position are located in different cells in a memory area of a device being formed on the specimen, and wherein selecting the one or more modes comprises performing cell-to-cell comparisons of the output acquired at the first position and the second position with the same modes.

7. The system of claim 1, wherein the inspection is a cell-to-cell inspection performed in a memory area of a device being formed on the specimen.

8. The system of claim 1, wherein the computer subsystem is further configured for aligning the acquired output generated by the detector at the second position with the first mode to the design data for the specimen.

9. The system of claim 1, wherein the first position is located within a first design-based care area, and wherein patterned features in the reference for the first position are the same as patterned features within the first design-based care area.

10. The system of claim 1, wherein the computer subsystem is further configured for determining an area of the first known defect in the acquired output generated by the detector at the first position with the first mode, the second mode, and the one or more additional modes based on results of said aligning the acquired output to the design data.

11. The system of claim 1, wherein the computer subsystem is further configured for overlaying the design data with the acquired output generated by the detector at the first position with the second mode and the one or more additional modes based on results of said aligning the acquired output to the design data.

12. The system of claim 1, wherein the computer subsystem is further configured for determining an area of the first known defect in the acquired output generated by the detector at the first position with the second mode and the one or more additional modes without aligning the acquired output generated by the detector at the first position with the second mode and the one or more additional modes to the design data.

13. The system of claim 1, wherein aligning the acquired output to the design data comprising overlaying the design data on the output acquired at the first position with the first mode, and wherein the computer subsystem is further configured for displaying results of said overlaying to a user and prompting the user to select an area of the first known defect in the acquired output based on the displayed results.

14. The system of claim 1, wherein the computer subsystem is further configured for determining an area of the reference for the first position in the acquired output generated by the detector at the second position with the first mode by aligning the acquired output generated by the detector at the second position with the first mode to the design data.

15. The system of claim 1, wherein the computer subsystem is further configured for performing steps h) through m) for another position on the specimen at which another reference for the first position is formed.

16. The system of claim 1, wherein the specimen comprises a wafer.

17. The system of claim 1, wherein the energy directed to the specimen comprises light, and wherein the energy detected from the specimen comprises light.

18. The system of claim 1, wherein the energy directed to the specimen comprises electrons, and wherein the energy detected from the specimen comprises electrons.

19. A non-transitory computer-readable medium, storing program instructions executable on a computer system for performing a computer-implemented method for selecting one or more modes of an inspection system for inspection of a specimen, wherein the computer system is a device having one or more processors executing the program instructions from the non-transitory computer-readable medium, and wherein the computer-implemented method comprises:

a) setting values for one or more parameters of the inspection system to a first mode known to generate output in which patterned features on the specimen are resolved to a degree that allows the output to be aligned to design data for the specimen, wherein the inspection system comprises at least an energy source, a detector, and a scanning subsystem, wherein the energy source is configured to generate energy that is directed to a specimen by the inspection system, wherein the detector is configured to detect energy from the specimen and to generate output responsive to the detected energy, wherein the scanning subsystem is configured to change a position on the specimen to which the energy is directed and from which the energy is detected, and wherein the scanning subsystem comprises a mechanical assembly configured to move the specimen and a stage on which the specimen is disposed;

b) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a first position on the specimen at which a first known defect is located;

c) acquiring the output generated by the detector at the first position with the first mode;

d) aligning the acquired output to the design data;

e) altering the values for the one or more parameters of the inspection system to a second mode different than the first mode;

f) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the first position, acquiring the output generated by the detector at the first position with the second mode;

g) repeating steps e) and f) for one or more additional modes of the inspection system;

h) setting the values for the one or more parameters of the inspection system to the first mode;

i) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a second position on the specimen at which a reference for the first position is formed;

j) acquiring the output generated by the detector at the second position with the first mode;

k) altering the values for the one or more parameters of the inspection system to the second mode;

l) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the second position, acquiring the output generated by the detector at the second position with the second mode;

m) repeating steps k) and l) for the one or more additional modes of the inspection system;

n) repeating steps a) through g) for one or more additional positions on the specimen at which one or more additional known defects are located;

o) repeating steps h) through m) for one or more further positions on the specimen at which one or more references for the one or more additional positions are formed; and

p) selecting one or more modes of the inspection system for inspection of the specimen or another specimen of the same type as the specimen based on all of the output generated by all of the steps of the computer-implemented method.

20. A method for selecting one or more modes of an inspection system for inspection of a specimen, comprising:

a) setting values for one or more parameters of the inspection system to a first mode known to generate output in which patterned features on the specimen are resolved to a degree that allows the output to be aligned to design data for the specimen, wherein the inspection system comprises at least an energy source, a detector, and a scanning subsystem, wherein the energy source is configured to generate energy that is directed to a specimen by the inspection system, wherein the detector is configured to detect energy from the specimen and to generate output responsive to the detected energy, wherein the scanning subsystem is configured to change a position on the specimen to which the energy is directed and from which the energy is detected, and wherein the scanning subsystem comprises a mechanical assembly configured to move the specimen and a stage on which the specimen is disposed;

b) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a first position on the specimen at which a first known defect is located;

c) acquiring the output generated by the detector at the first position with the first mode;

d) aligning the acquired output to the design data;

e) altering the values for the one or more parameters of the inspection system to a second mode different than the first mode;

f) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the first position, acquiring the output generated by the detector at the first position with the second mode;

g) repeating steps e) and f) for one or more additional modes of the inspection system;

h) setting the values for the one or more parameters of the inspection system to the first mode;

i) controlling the scanning subsystem such that the position on the specimen to which the energy is directed and from which the energy is detected is a second position on the specimen at which a reference for the first position is formed;

j) acquiring the output generated by the detector at the second position with the first mode;

k) altering the values for the one or more parameters of the inspection system to the second mode;

l) without changing the position on the specimen to which the energy is directed and from which the energy is detected from the second position, acquiring the output generated by the detector at the second position with the second mode;

m) repeating steps k) and l) for the one or more additional modes of the inspection system;

n) repeating steps a) through g) for one or more additional positions on the specimen at which one or more additional known defects are located;

o) repeating steps h) through m) for one or more further positions on the specimen at which one or more references for the one or more additional positions are formed; and

p) selecting one or more modes of the inspection system for inspection of the specimen or another specimen of the same type as the specimen based on all of the output generated by all of the steps of the computer-implemented method, wherein steps a) through p) are performed by a computer system, and wherein the computer system is a device having one or more processors executing instructions from a memory medium.