Positioning method, processing system, measurement method of substrate loading repeatability, position measurement method, exposure method, substrate processing apparatus, measurement method, and measurement apparatus

• US 20080013089A1
• Filed: 09/08/2006
• Published: 01/17/2008
• Est. Priority Date: 08/31/2004
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Ishii, Yuuki, Okita, Shinichi
• Application Number:
  US11/517,512
• Publication Number:
  US 20080013089A1
• Time in Patent Office: Days
• US Class Current: 356/400
• CPC Class Codes: G03F 9/7011 Pre-exposure scan; original with original holder alignment; Prealignment, i.e. workpiece with workpiece holder
• CPC Class Codes: G03F 9/7019 Calibration
• CPC Class Codes: H01L 21/681 using optical controlling means
• CPC Class Codes: H01L 21/682 Mask-wafer alignment in general G03F7/70, G03F9/70

Abstract

An edge of a surface to be measured of wafer and each of search alignment marks on the wafer are detected by an inline measurement instrument or the like that operates independently of an exposure apparatus, and position coordinates of the search marks in an X′Y′ coordinate system, which is a two-dimensional coordinate system substantially parallel to the surface to be measured and is set by a position of a notch of the wafer, are measured. Then, in pre-alignment performed when loading the wafer into the exposure apparatus, the edge of the wafer is detected, and from the detection results, position information of the object in the X′Y′ coordinate system is measured. Further, a relative position in the X′Y′ coordinate system of the wafer to be loaded into the exposure apparatus based on measurement results of the pre-alignment with respect to a measurement field of an alignment system that measures positions of the search marks on the wafer is adjusted based on measurement results of the inline measurement instrument or the like.

Claims

1. A positioning method, comprising:

a pre-measurement process in which before an object that has at least two marks formed on a surface to be measured thereof is loaded into a processing apparatus that performs predetermined processing to the object, at least a part of an outer edge of a surface to be measured of the object and each of the marks are detected, and a position coordinate of each of the marks in an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to the surface to be measured and is set by at least one datum point on the outer edge is measured based on the detection results;

a main measurement process in which at least a part of the outer edge of the surface to be measured of the object is detected, and position information of the object in the outer shape reference coordinate system is measured based on the detection results, in order to perform positioning of the object on loading of the object into the processing apparatus; and

an adjustment process in which a relative positional relation in the two-dimensional coordinate system of the object to be loaded into the processing apparatus based on the measurement results of the main measurement process with respect to a measurement field of a mark measurement unit that is arranged within the processing apparatus and measures a position of each of the marks on the object is adjusted, based on measurement results in the pre-measurement process.

2. The positioning method of claim 1 wherein

a shape of the outer edge of the surface to be measured of the object is a substantially circular shape,

the outer shape reference coordinate system is one of a coordinate system that is set by a center position and a rotation amount of the object obtained when using at least one specific point corresponding to an outer shape characteristic portion on the outer edge of the object as a datum point, and a coordinate system that is set by a center position and a rotation amount of the object obtained using at least three points on the outer edge of the object as datum points, and

in the pre-measurement process, measurement of the position coordinate of each of the marks in the outer shape reference coordinate system that is applied to the main measurement process is performed.

3. The positioning method of claim 1, further comprising:

a mark measurement process in which position measurement of each of the marks on the object loaded into the processing apparatus is performed; and

a post-loading judgment process in which based on the measurement results in the mark measurement process, the judgment is made of whether or not predetermined processing to the object can normally be performed.

4. The positioning method of claim 1, further comprising:

an evaluation process in which prior to the main measurement process, the detection results of at least a part of the outer edge of the surface to be measured of the object in the pre-measurement process is evaluated; and

an optimization process in which measurement conditions in the main measurement process are optimized, based on at least one of the detection results of at least a part of the outer edge of the surface to be measured of the object in the pre-measurement process and evaluation results in the evaluation process.

5. The positioning method of claim 4 wherein

in the evaluation process, the detection results are evaluated in a score form according to a predetermined evaluation criterion.

6. The positioning method of claim 5 wherein

in the evaluation process, the weighting sum of the plurality of characteristic amounts are computed as an evaluation result, using a plurality of characteristic amounts related to a detection state of the outer edge of the object in the detection results as the predetermined evaluation criterion.

7. The positioning method of claim 6 wherein

the plurality of characteristics amounts include at least one of contrast between a bright portion and a dark portion near the outer edge of the surface to be measured of the object that is obtained from the detection results, variation in the contrast, a curvature of the outer edge of the object that is obtained from the detection results, and variation between the outer edge and an approximate curve of the outer edge that is obtained from the detection results.

8. The positioning method of claim 4, further comprising:

a pre-optimization judgment process in which prior to the main measurement process, the judgment is made of whether or not detection of the outer edge of the object has normally been performed based on the scores of the detection results, and wherein

in the optimization process, in the case the judgment is denied, optimization of the measurement conditions is performed based on the detection results of at least a part of the outer edge of the surface to be measured of the object in the pre-measurement process.

9. The positioning method of claim 8, further comprising:

a post-optimization judgment process in which after performing the optimization process, the detection results of at least a part of the outer edge of the surface to be measured of the object to be loaded into the processing apparatus are evaluated again, and based on the evaluation results, the judgment is made of whether or not predetermined processing to the object can normally be performed.

10. The positioning method of claim 9 wherein

each of the processes is sequentially performed to each of objects included in an object group that is made up of a plurality of the objects, and

the positioning method further comprising:

an exclusion process in which all the objects included in the object group are excluded in the case the number of the objects to which the judgment is made that predetermined processing cannot be performed in the post-optimization judgment process exceeds a predetermined number.

11. The positioning method of claim 4, further comprising:

a consistency process in which the evaluation results with respect to the detection results of at least a part of the outer edge of the surface to be measured of the object in the pre-measurement process are made to be consistent with the evaluation results with respect to the detection results of at least a part of the outer edge of the surface to be measured of the object in the main measurement process.

12. The positioning method of claim 4 wherein

the optimization process is performed by at least one of the processing apparatus and an analytical apparatus that operates independently of the processing apparatus.

13. The positioning method of claim 4 wherein

the measurement conditions include at least one of an illumination condition at the time of measurement, the number of repeated measurement times, an imaging magnification of an imaging unit used for measurement and a position measurement algorithm.

14. The positioning method of claim 1 wherein

each of the processes is sequentially performed to each of a plurality of different objects, and

the positioning method further comprising:

a normalization process in which the position measurement results in the mark measurement process are normalized, based on the position coordinate of each of the marks in the outer shape reference coordinate system in the pre-measurement process; and

a repeatability measurement process in which repeatability of a relative positional relation of the object loaded into the processing apparatus with respect to the measurement field of the mark measurement unit is measured, based on the normalized position measurement results.

15. The positioning method of claim 14 wherein

on the object, a plurality of divided areas formed in a matrix arrangement, fine alignment marks arranged along with the respective divided areas and search alignment marks used to search the fine alignment marks are formed, and

the positioning method further comprising:

a detection process in which each of the marks measured in the pre-measurement process is used as the search alignment mark, and an array coordinate system that is set by an array of the plurality of divided areas on the object is detected using a predetermined statistical method, based on position measurement results of at least three fine alignment marks that are noncollinear and formed on the object loaded into the processing apparatus, and wherein

in the normalization process, the measurement results in the mark measurement process are further normalized based on at least one of a magnification component and an orthogonal component of the array coordinate system with respect to the outer shape reference coordinate system.

16. The positioning method of claim 15 wherein

in the detection process, a random component of the position measurement result of each of the search alignment marks with respect to the array coordinate system is obtained, and

in the normalization process, the measurement results in the mark measurement process are further normalized based on the random component.

17. The positioning method of claim 16, further comprising:

a repeatability measurement judgment process in which based on magnitude of the random component, the judgment is made of whether or not the position measurement result of each of the marks is used for repeatability measurement.

18. The positioning method of claim 14, further comprising:

a derivation process in which a fluctuation prediction equation that is used to predict fluctuation in a center position and a rotation amount of the object based on variation in the normalized position measurement results in the mark measurement process is derived, and wherein

in the adjustment process, a relative positional relation between the object to be loaded into the processing apparatus and the measurement field of the mark measurement unit that measures a position of each of the marks on the object is adjusted, based on calculation results of the fluctuation prediction equation.

19. The positioning method of claim 14 wherein

in the repeatability measurement process, as an evaluation factor of the repeatability, information related to standard deviation, a range and a mean of a center position and a rotation amount of the object after loading is used.

20. The positioning method of claim 19, further comprising:

a judgment process in which based on a value of the evaluation factor, the judgment is made of whether or not a predetermined processing can normally be performed to the object.

21. The positioning method of claim 1 wherein

the pre-measurement process is performed after the object is coated with a photosensitive agent.

22. The positioning method of claim 21 wherein

a timing of performing the pre-measurement process is made to be different from a timing of performing measurement of a pattern on the object to which predetermined processing and development are completed.

23. The positioning method of claim 1 wherein

the processing apparatus is an exposure apparatus that exposes a photosensitive substrate as the object,

a measurement apparatus that performs the pre-measurement process is inline connected to the exposure apparatus.

24. The positioning method of claim 23 wherein the processing apparatus further includes at least one of a measurement apparatus that performs measurement processing to a photosensitive substrate after exposure that has been through exposure processing in the exposure apparatus, an inspection apparatus that performs inspection processing to a photosensitive substrate after exposure, a test apparatus that performs test processing to the photosensitive substrate after exposure, and a repair apparatus that performs repair processing to the photosensitive substrate after exposure.

25. A processing system, comprising:

a processing apparatus that performs predetermined processing to an object;

a mark measurement unit that performs position measurement of at least two marks formed on the object loaded into the processing apparatus;

a pre-measurement apparatus that, before the object that has at least two marks formed on a surface to be measured thereof is loaded into the processing apparatus, detects at least a part of an outer edge of the surface to be measured of the object and each of the marks, and measures a position coordinate of each of the marks in an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to the surface to be measured and is set by at least one datum point on the outer edge of the object, based on the detection results;

an outer edge measurement unit that detects at least a part of the outer edge of the surface to be measured of the object, and measures position information of the object in the outer shape reference coordinate system based on the detection results, in order to perform positioning of the object on loading of the object into the processing apparatus; and

an adjustment unit that adjusts a relative positional relation in the two-dimensional coordinate system of the object to be loaded into the processing apparatus based on the measurement results of the outer edge measurement unit with respect to a measurement field of the mark measurement unit, based on measurement results of the pre-measurement apparatus.

26. The processing system of claim 25, further comprising:

an evaluation apparatus that evaluates the detection results of at least a part of the outer edge of the surface to be measured of the object by the pre-measurement apparatus; and

an optimization apparatus that optimizes measurement conditions in the outer edge measurement unit based on at least one of the detection results of at least a part of the outer edge of the surface to be measured of the object by the pre-measurement apparatus and evaluation results by the evaluation apparatus.

27. The processing system of claim 26, further comprising:

a normalization unit that normalizes the position measurement results of the mark measurement unit based on the position coordinate of each of the marks in the outer shape reference coordinate system in the pre-measurement apparatus; and

a repeatability measurement unit that measures repeatability of positioning of the object loaded into the processing apparatus, based on the normalized position measurement results.

28. The processing system of claim 25, further comprising:

a derivation unit that derives a fluctuation prediction equation used to predict fluctuation in a center position and a rotation amount of the object based on variation in the normalized position measurement results of the mark measurement unit, and wherein

the adjustment unit adjusts a relative positional relation of the object to be loaded into the processing apparatus with respect to a measurement field of a measurement unit that measures a position of each of the marks on the object, based on calculation results of the fluctuation prediction equation.

29. The processing system of claim 25 wherein

the processing apparatus is an exposure apparatus that exposes a photosensitive substrate as the object,

the pre-measurement apparatus is inline connected to the exposure apparatus.

30. The processing system of claim 29 wherein the processing apparatus further includes at least one of a measurement apparatus that performs measurement processing to a photosensitive substrate after exposure that has been through exposure processing in the exposure apparatus, an inspection apparatus that performs inspection processing to a photosensitive substrate after exposure, a test apparatus that performs test processing to the photosensitive substrate after exposure, and a repair apparatus that performs repair processing to the photosensitive substrate after exposure.

31. A measurement method of substrate loading repeatability in which repeatability of a loading position of a substrate that is loaded to a datum position arranged within a substrate processing apparatus, the method comprising:

a position setting process in which positions of a plurality of the substrates on which a device pattern is to be sequentially transferred are sequentially set to the datum position;

a measurement process in which position information of a mark that is formed on the substrate loaded to the datum position is sequentially measured by a measurement instrument arranged within the substrate processing apparatus; and

a computation process in which the loading repeatability is computed based on measurement results of the measurement process.

32. The measurement method of substrate loading repeatability of claim 31, further comprising:

a normalization process in which variation in the measurement results of the measurement process based on a difference of an outer shape of each substrate between the plurality of substrates is normalized, and wherein

based on normalization results in the normalization process, the loading repeatability is computed.

33. The measurement method of substrate loading repeatability of claim 32 wherein

the mark is arranged in plural on the substrate, and

the normalization process includes:

a process in which a contour of the substrate is measured, and based on the measurement result, an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to a surface of the substrate and is set by at least one datum point on the contour is set, and

a process in which position information of the plurality of marks in the outer shape reference coordinate system is measured, and

in the normalization process, variation in a measurement result of each of the plurality of marks is normalized based on the position information of each of the plurality of marks in the outer shape reference coordinate system, and

in the computation process, the loading repeatability is computed based on the normalized position information.

34. The measurement method of substrate loading repeatability of claim 31, further comprising:

a normalization process in which variation in the measurement results of the measurement process based on a difference of a deformation component of each substrate itself between the plurality of substrates is normalized, and wherein

the loading repeatability is computed based on normalization results in the normalization process.

35. The measurement method of substrate loading repeatability of claim 34 wherein

on the substrate, a plurality of divided areas formed in a matrix arrangement, fine alignment marks arranged along with the respective divided areas and search alignment marks used to search the fine alignment marks are formed, and

the measurement method of loading repeatability further comprising:

a detection process in which an array coordinate system that is set by an array of the plurality of divided areas on the substrate is detected using a predetermined statistical method, based on position measurement results of the fine alignment marks in at least two different points or at least three noncollinear points that are formed on the substrate loaded into the substrate processing apparatus, and wherein

the normalization process includes;

a process in which a contour of the substrate is measured, and based on the measurement result, an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to a surface of the substrate and is set by at least one datum point on the contour is set, and

a process in which position information of the plurality of search alignment marks in the outer shape reference coordinate system is measured, and

in the normalization process, variation in the measurement results of the measurement process are further normalized, based on at least one of a magnification component and an orthogonal component of the array coordinate system with respect to the outer shape reference coordinate system.

36. The measurement method of substrate loading repeatability of claim 35 wherein

in the detection process, a random component of the position measurement result of each of the marks with respect to the array coordinate system is obtained, and

in the normalization process, the measurement results of the measurement process are further normalized based on magnitude of the random component.

37. A position measurement method in which position information that indicates a position of a substrate whose position is set to a predetermined datum position is measured, the method comprising:

a process in which loading repeatability of the substrate disposed at the datum position is measured using the measurement method of substrate loading repeatability according to claim 31;

and

a process in which the position of the substrate is adjusted in accordance with tendency of the loading repeatability, and position information of a mark formed on the substrate is measured.

38. An exposure method in which a predetermined pattern is transferred onto a substrate, the method comprising:

a substrate measurement process in which position information that indicates a position of the substrate is obtained using the position measurement method according to claim 37;

and

a transfer process in which position control of the substrate is performed based on the position information of the substrate obtained in the substrate measurement process, and the pattern is transferred onto the substrate.

39. A substrate processing apparatus that sequentially processes a plurality of substrates, the apparatus comprising:

a position setting unit that sequentially sets positions of the substrates to a predetermined datum position;

a measurement unit that measures position information of a mark formed on the substrate whose position is set to the datum position; and

a computation unit that computes loading repeatability of the substrate based on measurement results of the measurement unit.

40. The substrate processing apparatus of claim 39, further comprising:

a normalization unit that normalizes variation in the measurement results of the measurement unit based on a difference of an outer shape of each substrate or a difference of a deformation component of each substrate itself between the plurality of substrates, and wherein

the loading repeatability is computed based on normalization results of the normalization unit.

41. A measurement method, comprising:

a first process in which at least a part of an outer edge of a surface to be measured of an object that has a mark formed on the surface to be measured thereof is measured;

a second process in which the mark is measured; and

a third process in which position information of the mark in an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to the surface to be measured and is set by at least one datum point on the outer edge is obtained based on measurement results of the first and second processes.

42. The measurement method of claim 41 wherein

at least the first process and the second process are performed before the object is loaded into a processing apparatus that performs predetermined processing to the object.

43. The measurement method of claim 42 wherein

at least one information from among the position information of the mark computed in the third process, the measurement results of the first process, and evaluation results obtained by evaluating the measurement results of the first process in a predetermined evaluation method is sent to the processing apparatus.

44. The measurement method of claim 41 wherein

the first process and the second process are performed substantially at the same time.

45. A measurement method, comprising:

a first process in which at least a part of an outer edge of an object is measured before the object is loaded into a processing apparatus that performs predetermined processing to the object; and

a second process in which measurement results of the first process and/or evaluation results obtained by evaluating the measurement results of the first process in a predetermined evaluation method are/is sent to the processing apparatus.

49. The measurement method of claim 45 wherein

the processing apparatus includes an exposure apparatus that exposes a photosensitive substrate as the object.

50. The measurement method of claim 49 wherein the processing apparatus further includes at least one of a measurement apparatus that performs measurement processing to a photosensitive substrate after exposure that has been through exposure processing in the exposure apparatus, an inspection apparatus that performs inspection processing to a photosensitive substrate after exposure, a test apparatus that performs test processing to the photosensitive substrate after exposure, and a repair apparatus that performs repair processing to the photosensitive substrate after exposure.

46. A measurement apparatus, comprising:

a first measurement sensor that measures at least a part of an outer edge of a surface to be measured of an object that has a mark formed on the surface to be measured thereof;

a second measurement sensor that measures the mark; and

a computation unit that obtains position information of the mark in an outer shape reference coordinate system that is a two-dimensional coordinate system substantially parallel to the surface to be measured and is set by at least one datum point on the outer edge, based on measurement results of the first and second sensors.

47. The measurement apparatus of claim 46 wherein

the measurement apparatus is arranged outside a processing apparatus that performs predetermined processing to the object, and

the measurement apparatus further comprises:

a transmission unit that sends at least one of the position information of the mark, the measurement results of the first measurement sensor, and evaluation results obtained by evaluating the measurement results of the first measurement sensor in a predetermined evaluation method to the processing apparatus.

51. The measurement apparatus of claim 47 wherein

the processing apparatus includes an exposure apparatus that exposes a photosensitive substrate as the object.

52. The measurement apparatus of claim 51 wherein the processing apparatus further includes at least one of a measurement apparatus that performs measurement processing to a photosensitive substrate after exposure that has been through exposure processing in the exposure apparatus, an inspection apparatus that performs inspection processing to a photosensitive substrate after exposure, a test apparatus that performs test processing to the photosensitive substrate after exposure, and a repair apparatus that performs repair processing to the photosensitive substrate after exposure.

48. A measurement apparatus, comprising:

a sensor that is disposed outside a processing apparatus that performs predetermined processing to an object and measures at least a part of an outer edge of the object before the object is loaded into the processing apparatus; and

a transmission unit that sends measurement results of the sensor and/or evaluation results obtained by evaluating the measurement results of the sensor in a predetermined evaluation method to the processing apparatus.