Scanning exposure apparatus

• US 20030133088A1
• Filed: 01/27/2003
• Published: 07/17/2003
• Est. Priority Date: 03/24/2000
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Okita, Shinichi, Hagiwara, Tsuneyuki
• Granted Patent: US 6,992,751 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70691 Handling of masks or workpieces
• 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 9/7026 Focusing

Abstract

A scanning exposure apparatus which promptly analyzes a cause for a variation in exposure line width. The scanning exposure apparatus includes a mask stage on which a mask is placed, a wafer stage on which a wafer is placed, a focusing mechanism which detects surface position information of the wafer and adjustment means which adjusts the surface position of the wafer. Control means acquires pose information of the wafer adjusted by the adjustment means at the time of exposure and stores the pose information in a memory in association with preacquired surface shape information of an exposure area. A state in which the exposed surface of the wafer has been exposed with respect to exposure light is known from the pose information and the surface shape information.

Claims

1. A scanning exposure apparatus for projecting an image of a pattern of a mask on a substrate using exposure light and scanning the substrate with the exposure light to expose an exposure area on the substrate, comprising:

surface position detection means for detecting surface position information of the substrate;

adjustment means for adjusting a surface position of the substrate based on a result of detection by the surface position detection means; and

control means for acquiring pose information of the substrate adjusted by the adjustment means at a time of exposure based on a detection signal from the surface position detection means and storing the pose information in a memory in association with preacquired surface shape information of the exposure area on the substrate.

2. The scanning exposure apparatus according to claim 1, wherein the control means includes image-state prediction means for predicting a state of the image of the pattern transferred on the substrate based on the pose information and the surface shape information.

3. The scanning exposure apparatus according to claim 2, wherein the pose information includes a trace error of the substrate with respect to a control target position of the substrate which is adjusted by the adjustment means.

4. The scanning exposure apparatus according to claim 3, wherein the control means computes at least one of an average deviation amount of an optical-axial directional position of the substrate with respect to a target position at a plurality of measuring points on an exposure surface of the substrate during irradiation of the exposure light and a standard deviation of a fluctuation component of the optical-axial directional position during irradiation of the exposure light, based on the trace error and the surface shape information.

5. The scanning exposure apparatus according to claim 4, wherein the control means further includes a data storage section for prestoring at least one of the average deviation amount and the standard deviation of the fluctuation component and data of the state of the image of the pattern transferred on the substrate in association with each other, and the image-state prediction means predicts the state of the image of the pattern exposed, based on the state data of the image of the pattern stored in the data storage section and at least one of the average deviation amount and the standard deviation of the fluctuation component which have been acquired during exposure or after exposure.

6. The scanning exposure apparatus according to claim 1, wherein the state of the image of the pattern includes line width information of the pattern formed on the substrate.

7. The scanning exposure apparatus according to claim 2, wherein the image-state prediction means includes image-forming simulation means for computing the state of the image of the pattern based on data including a performance of a projection optical system, an illumination condition for illuminating the mask and a designed line width of the pattern.

8. The scanning exposure apparatus according to claim 2, further comprising decision means for deciding that exposure is abnormal when the state of the image of the pattern predicted by the image-state prediction means goes off a predetermined allowable range.

9. The scanning exposure apparatus according to claim 2, further comprising display means for displaying the state of the image of the pattern predicted by the image-state prediction means by at least one of numerical data, a two-dimensional expression and a three-dimensional expression.

10. A scanning exposure method of projecting an image of a mask pattern on a substrate using exposure light and relatively scanning the substrate with the exposure light to expose an exposure area on the substrate, comprising the steps of:

detecting a surface position of the substrate at a time of exposure and detecting pose information of the substrate; and

predicting a state of the image of the pattern formed on the substrate based on the detected pose information and preacquired surface shape information in an exposure area of the substrate.

11. The scanning exposure method according to claim 10, wherein data of the state of the image of the pattern transferred on the substrate is prestored in association with pose error information acquired from the pose information and the surface shape information, and the state of the image of the pattern formed on the substrate is predicted based on the stored data.

12. The scanning exposure method according to claim 11, wherein the pose error information includes at least one of an average deviation amount of an optical-axial directional position of the substrate with respect to a target position at a plurality of measuring points on an exposure surface of the substrate during irradiation of the exposure light and a standard deviation of a fluctuation component of the optical-axial directional position during irradiation of the exposure light.

13. The scanning exposure method according to claim 10, wherein the state of the image of the pattern includes line width information of the pattern formed on the substrate.

14. The scanning exposure method according to claim 10, further comprising the step of deciding that exposure is abnormal when the predicted state of the image of the pattern goes off a predetermined allowable range.

15. A management apparatus for managing exposure process information of a scanning exposure apparatus which includes surface position detection means for detecting surface position information of a substrate and adjustment means for adjusting a surface position of the substrate based on a result of detection by the surface position detection means, the scanning exposure apparatus projecting an image of a pattern of a mask on the substrate using exposure light and scanning the substrate with the exposure light to expose an exposure area on the substrate, the management apparatus comprising:

an interface connected to the scanning exposure apparatus; and

control means for acquiring pose information of the substrate adjusted by the adjustment means at a time of exposure based on a detection signal from the surface position detection means acquired via the interface, and storing the pose information in a memory in association with preacquired surface shape information of the exposure area on the substrate.

16. The management apparatus according to claim 15, wherein the control means includes image-state prediction means for predicting a state of the image of the pattern transferred on the substrate based on the pose information and the surface shape information.

17. The management apparatus according to claim 16, wherein data of the state of the image of the pattern transferred on the substrate is prestored in association with pose error information acquired from the pose information and the surface shape information, and the image-state prediction means predicts the state of the image of the pattern formed on the substrate based on the stored data.

18. The management apparatus according to claim 17, wherein the pose error information includes at least one of an average deviation amount of an optical-axial directional position of the substrate with respect to a target position at a plurality of measuring points on an exposure surface of the substrate during irradiation of the exposure light and a standard deviation of a fluctuation component of the optical-axial directional position during irradiation of the exposure light.

19. The management apparatus according to claim 16, wherein the state of the image of the pattern includes line width information of the pattern formed on the substrate.

20. The management apparatus according to claim 16, further comprising decision means for deciding that exposure is abnormal when the predicted state of the image of the pattern goes off a predetermined allowable range.

21. A management method of managing exposure process information of a scanning exposure apparatus which includes surface position detection means for detecting surface position information of a substrate and adjustment means for adjusting a surface position of the substrate based on a result of detection by the surface position detection means, the scanning exposure apparatus projecting an image of a pattern of a mask on the substrate using exposure light and scans the substrate with the exposure light to expose an exposure area on the substrate, the management method comprising the steps of:

acquiring a detection signal of the surface position detection means via an interface from the scanning exposure apparatus;

acquiring pose information of the substrate adjusted by the adjustment means at a time of exposure; and

predicting a state of the image of the pattern formed on the substrate based on the pose information and preacquired surface shape information of the exposure area on the substrate.

22. The management method according to claim 21, wherein data on the state of the image of the pattern transferred on the substrate is prestored in association with pose error information acquired from the pose information and the surface shape information, and the state of the image of the pattern formed on the substrate is predicted based on the stored data.

23. The management method according to claim 22, wherein the pose error information includes at least one of an average deviation amount of an optical-axial directional position of the substrate with respect to a target position at a plurality of measuring points on an exposure surface of the substrate during irradiation of the exposure light and a standard deviation of a fluctuation component of the optical-axial directional position during irradiation of the exposure light.

24. The management method according to claim 21, wherein the state of the image of the pattern includes line width information of the pattern formed on the substrate.

25. The management method according to claim 21, further comprising the step of deciding that exposure is abnormal when the predicted state of the image of the pattern goes off a predetermined allowable range.

26. A device manufacturing method comprising the step of:

executing a lithography process using a scanning exposure method of projecting an image of a mask pattern on a substrate using exposure light and relatively scanning the substrate with the exposure light to expose an exposure area on the substrate, the scanning exposure method including the steps of;

detecting pose information of the substrate by detecting a surface position of the substrate at a time of exposure; and

predicting a state of the image of the pattern formed on the substrate based on the detected pose information and preacquired surface shape information in an exposure area of the substrate.

27. A device manufacturing method comprising the step of:

executing a lithography process using a management method of managing exposure process information of a scanning exposure apparatus which includes surface position detection means for detecting surface position information of a substrate and adjustment means for adjusting a surface position of the substrate based on a result of detection by the surface position detection means, the scanning exposure apparatus projecting an image of a pattern of a mask on the substrate using exposure light and scanning the substrate with the exposure light to expose an exposure area on the substrate, the management method including the steps of;

acquiring a detection signal of the surface position detection means via an interface from the scanning exposure apparatus;

acquiring pose information of the substrate adjusted by the adjustment means at a time of exposure; and

predicting a state of the image of the pattern formed on the substrate based on the pose information and preacquired surface shape information of the exposure area on the substrate.