Control method, control system, and program

• US 7,941,232 B2
• Filed: 09/15/2006
• Issued: 05/10/2011
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Okita, Shinichi, Ishii, Yuuki
• Primary Examiner(s): DeCady; Albert
• Assistant Examiner(s): CHANG, SUNRAY
• Application Number:
  US11/521,511
• Publication Number:
  US 20080221709A1
• Time in Patent Office: 1,698 Days
• Field of Search: 430/5, 430/22, 430/30, 356/124, 356/125, 700/28, 700/29, 382/144, 382/145, 382/149
• US Class Current: 700/29
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70533 Controlling abnormal operating mode, e.g. taking account of waiting time, decision to rework or rework flow
• CPC Class Codes: G03F 7/70641 Focus
• CPC Class Codes: G03F 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load

Abstract

By repeatedly executing a predetermined measurement at set intervals, data on a predetermined performance (a best focus position) of a predetermined apparatus and data on variation factors of the performance are obtained (Steps 204 to 214). Based on the obtained data, multivariate analysis is performed and a model equation that is used to predict a variation amount of the performance and includes at least one of the variation factors as a variable is derived (Step 214). Therefore, after deriving the model equation, a variation amount of the performance can be predicted using the model equation by obtaining data on the variation factor that serves as the variable (Step 238). Accordingly, it becomes possible to maintain the performance described above with good accuracy in accordance with the prediction results and also optimize the implementation timing of maintenance and the like.

Claims

1. A control method of controlling a quality criteria of a predetermined apparatus that is installed in a clean room to manufacture micro-devices, the method comprising:

obtaining data related to a predetermined quality criteria, which includes at least one of an image-forming quality criteria of an optical system and a position control quality criteria of a stage which moves while an object is mounted thereon, and which has environmental conditions serving as variation factors, and data on the environmental conditions, by repeatedly executing a predetermined measurement at least one of at a set timing and at set intervals, wherein the predetermined apparatus comprises the optical system and the stage, and the environmental conditions include at least one of temperature, humidity and pressure in a controlled environment where the micro-devices are manufactured;

deriving a model equation used to predict a variation amount of the predetermined quality criteria that includes at least one of the environmental conditions as a variable, by performing multivariate analysis based on the obtained data;

obtaining data on the environmental condition that is the variable at a predetermined timing during operation of the predetermined apparatus, and computing a variation amount of the quality criteria based on the obtained data and the model equation;

adjusting an implementation timing of the predetermined measurement so that an implementation interval of the predetermined measurement lengthens in the case the variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and an implementation interval of the predetermined measurement shortens in the case the variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance; and

controlling the quality criteria of the predetermined apparatus based on the model equation.

2. The control method of 2 claim 1, further comprising:

executing the predetermined measurement at the implementation interval adjusted based on the computed variation amount.

3. The control method of claim 1 wherein

a period of time required for the predetermined measurement is optimized based on a variation amount of the quality criteria computed using the model equation.

4. The control method of claim 3 wherein

a period of time required for the predetermined measurement is shortened in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and

a period of time required for the predetermined measurement is extended in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance.

5. The control method of Claim 1, further comprising:

correcting the quality criteria based on the computed variation amount.

6. The control method of Claim 1 wherein

the number of the obtained data is optimized based on a variation amount of the quality criteria computed using the model equation.

7. The control method of claim 6 wherein

in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, the number of the obtained data is decreased, and

in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance, the number of the obtained data is increased.

8. The control method of claim 1 wherein

the predetermined measurement is executed at the time of maintenance of the predetermined apparatus.

9. The control method of claim 1 wherein

the predetermined apparatus is an exposure apparatus, and

the predetermined quality criteria is at least one of an offset of a detection origin of a measurement device that measures a positional relation between an image plane of a projection optical system and an object to be exposed with respect to an optical axis direction of the projection optical system, a best focus position of the projection optical system, and a focus offset of the projection optical system.

10. The control method of claim 9 wherein

the data related to the predetermined quality criteria is data on at least one of an offset of the detection origin of the measurement device and the best focus position, which are obtained as a result of executing at least one of measurement of an aerial image of a predetermined pattern and measurement of a transferred image of a predetermined pattern that is obtained as a result of a test exposure.

11. The control method of claim 9 wherein

the data related to the predetermined quality criteria is data on at least one of an offset of the detection origin of the measurement device and the best focus position, which are obtained based on data after conversion in which measurement data on the aerial image of the predetermined pattern is converted into measurement data on the transferred image of the predetermined pattern that is obtained as a result of the test exposure based on a known relation between the measurement data on the aerial image and the measurement data on the transferred image.

12. The control method of claim 1, wherein

the predetermined apparatus is an exposure apparatus, and

the predetermined quality criteria is a position control quality criteria of a stage on which an object to be exposed is mounted.

13. A control system that controls a quality criteria of a predetermined apparatus that is installed in a clean room to manufacture micro-devices, the system comprising:

a data obtaining device that obtains data related to a predetermined quality criteria, which includes at least one of an image-forming quality criteria of an optical system and a position control quality criteria of a stage which moves while an object is mounted thereon, and which has environmental conditions serving as variation factors, and data on the environmental conditions, by repeatedly executing a predetermined measurement at least one of at a set timing and at set intervals, wherein the predetermined apparatus comprises the optical system and the stage, and the environmental conditions include at least one of temperature, humidity and pressure in a controlled environment where the micro-devices are manufactured;

a model equation deriving device that derives a model equation used to predict a variation amount of the predetermined quality criteria that includes at least one of the environmental conditions as a variable, by performing multivariate analysis based on the obtained data;

a variation amount computing device that obtains data on the environmental condition that is the variable at a predetermined timing during operation of the predetermined apparatus, and computes a variation amount of the quality criteria based on the obtained data and the model equation;

an adjustment device that adjusts an implementation timing of the predetermined measurement so that an implementation interval of the predetermined measurement lengthens in the case the variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and an implementation interval of the predetermined measurement shortens in the case the variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance; and

a processing device that controls the quality criteria of the predetermined apparatus based on the model equation.

14. The control system of claim 13 , further comprising:

a measurement executing device that executes the predetermined measurement at the implementation interval adjusted based on the computed variation amount.

15. The control system of claim 13 wherein

a period of time required for the predetermined measurement is optimized based on a variation amount of the quality criteria computed using the model equation.

16. The control system of claim 15, further comprising:

a measurement time changing device that shortens a period of time required for the predetermined measurement in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and extends a period of time required for the predetermined measurement in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance.

17. The control system of claim 13, further comprising:

a correction device that corrects the quality criteria based on the computed variation amount.

18. The control system of Claim 13 wherein

the number of the obtained data is optimized based on a variation amount of the quality criteria computed using the model equation.

19. The control system of claim 18 wherein

in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, the number of the obtained data is decreased, and

in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance, the number of the obtained data is increased.

20. The control system of claim 13 wherein

the predetermined measurement is executed at the time of maintenance of the predetermined apparatus.

21. The control system of claim 13, further comprising:

a computer that online connects to the predetermined apparatus, wherein

at least a part of the data obtaining device and the model equation deriving device is arranged in one of the predetermined apparatus and the computer.

22. The control system of claim 13, wherein

the predetermined apparatus is an exposure apparatus, and

the control system further comprises:

an image measurement device that online connects to the predetermined apparatus and measures a transferred image of a pattern that is formed on an object to be exposed, wherein

at least a part of the data obtaining device and the model equation deriving device is arranged in the image measurement device.

23. The control system of claim 13, wherein

the predetermined apparatus is an exposure apparatus, and

the predetermined quality criteria is at least one of an offset of a detection origin of a measurement device that measures a positional relation between an image plane of the projection optical system and an object to be exposed with respect to an optical axis direction of a projection optical system, a best focus position of the projection optical system, and a focus offset of the projection optical system.

24. A computer readable storage medium storing an executable program that controls a quality criteria of a predetermined apparatus installed in a clean room to manufacture micro-devices, the program causing a computer to execute:

obtaining data related to a predetermined quality criteria, which includes at least one of an image-forming quality criteria of an optical system and a position control quality criteria of a stage which moves while an object is mounted thereon, and which has environmental conditions serving as variation factors, and data on the environmental conditions, by repeatedly executing a predetermined measurement at least one of at a set timing and at set intervals, wherein the predetermined apparatus comprises the optical system and the stage, and the environmental conditions include at least one of temperature, humidity and pressure in a controlled environment where the micro-devices are manufactured;

deriving a model equation, by performing multivariate analysis to determine an undetermined coefficient in the model equation used to predict a variation amount of the predetermined quality criteria that includes at least one of the environmental conditions as a variable, based on the obtained data;

obtaining data on the environmental condition that is the variable at a predetermined timing during operation of the predetermined apparatus, and computing a variation amount of the quality criteria based on the obtained data and the model equation;

performing a timing adjustment that shortens a period of time required for the predetermined measurement in the case the variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and that extends a period of time required for the predetermined measurement in the case the variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance; and

controlling the quality criteria of the predetermined apparatus based on the model equation.

25. The computer readable storage medium of Claim 24, wherein the program further causes the computer to execute:

executing the predetermined measurement at an implementation timing adjusted based on the computed variation amount.

26. The computer readable storage medium of Claim 24, wherein the program further causes the computer to execute:

optimizing a period of time required for the predetermined measurement based on a variation amount of the quality criteria computed using the model equation.

27. The computer readable storage medium of claim 26, wherein the program further causes the computer to execute:

a timing adjustment that shortens a period of time required for the predetermined measurement in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and that extends a period of time required for the predetermined measurement in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance.

28. The computer readable storage medium of Claim 24, wherein the program further causes the computer to execute:

optimizing the number of the obtained data based on a variation amount of the quality criteria computed using the model equation.

29. The computer readable storage medium of claim 28, wherein the program further causes the computer to execute:

a data adjustment that decreases the number of the obtained data in the case a variation amount of the quality criteria computed using the model equation does not exceed a value set in advance predetermined times in a row, and that increases the number of the obtained data in the case a variation amount of the quality criteria computed using the model equation exceeds a permissible value set in advance.

30. The computer readable storage medium of claim 24, wherein the program causes the computer to execute the predetermined measurement at the time of maintenance of the predetermined apparatus.