Method of measuring the position of a mask surface along the height direction, exposure device, and exposure method

• US 8,390,783 B2
• Filed: 09/08/2008
• Issued: 03/05/2013
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Hirayanagi, Noriyuki, Tanaka, Keiichi
• Primary Examiner(s): Nguyen, Hung Henry
• Assistant Examiner(s): KREUTZER, COLIN WRIGHT
• Application Number:
  US12/206,720
• Publication Number:
  US 20090015810A1
• Time in Patent Office: 1,639 Days
• Field of Search: 250/492.2, 355/53, 355/55, 355 60- 61, 355 66- 67, 355/71, 355/77, 356399-401, 359232-233, 359/361
• US Class Current: 355/61
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70783 Handling stress or warp of chucks, masks or workpieces, e.g. to compensate for imaging errors or considerations related to warpage of masks or workpieces due to their own weight
• CPC Class Codes: G03F 9/7026 Focusing
• CPC Class Codes: G03F 9/7034 Leveling

Abstract

A method to measure the height-direction position of a mask M in an exposure device having a function to irradiate the mask M with light emitted from a light source and transfer a pattern formed on the mask M onto a photosensitive substrate such as a wafer by a projection optical system, a mask surface height-direction position measurement method characterized by moving, before measuring the height-direction position of the mask M, an exposure area defining member 1 which is installed between the mask M and the projection optical system and defines an exposure area at the time of exposure.

Claims

1. An exposure device for exposing a photosensitive substrate with a reflection mask pattern, comprising:

a projection optical system configured to project the reflection mask pattern, the projection optical system comprising an exposure area defining member configured to define a shape of light incident on the photosensitive substrate;

a height-direction position measuring device configured to measure a height position of the reflection mask at a position where a measuring light is not obstructed by the exposure area defining member, and configured to measure a measurement area defined on the mask that is greater than the area of the shape of light defined by the exposure area defining member wherein the measuring light reaches a surface of the mask which includes the area of the shape of light defined by the exposure area defining member and a peripheral region of the area of the shape of light defined by the exposure area defining member; and

a mover configured to move the reflection mask according to the height position of the reflection mask as measured by the height-direction position measuring device.

2. An exposure device for exposing a photosensitive substrate with a reflection mask pattern, comprising:

a projection optical system;

a height-direction position measuring device configured to measure a height position of a reflection mask;

an exposure area defining member between the reflection mask and the projection optical system configured to define a shape of the light incident on the photosensitive substrate at the time of exposure;

a mover configured to move the exposure defining member; and

a controller configured to control the mover so as to move the exposure defining member to a first position at the time of exposure and to move the exposure area defining member to a second position where a measuring light is not obstructed by the exposure area defining member at the time of measuring the height direction position of the reflection mask wherein the measuring light reaches a surface of the mask which includes the area of the shape of light defined by the exposure area defining member and a peripheral region of the area of the shape of light defined by the exposure area defining member.

3. An exposure device for exposing a photosensitive substrate with a reflection mask pattern, comprising:

a projection optical system configured to project the reflection mask pattern, the projection optical system comprising an exposure area defining member configured to define a shape of light incident on the photosensitive substrate;

a first measurement device comprising optical elements configured to measure the height-direction position of an area of the reflection mask that is greater than the area of the shape of light defined by the exposure area defining member at a position where a measuring light is not obstructed by the exposure area defining member wherein the measuring light reaches a surface of the mask which includes the area of the shape of light defined by the exposure area defining member and a peripheral region of the area of the shape of light defined by the exposure area defining member;

a second measurement device configured to measure the height-direction position of the photosensitive substrate; and

a controller configured to adjust the height-direction position of the reflection mask based on the measured height-direction position of the reflection mask, and to adjust the height-direction position of the photosensitive substrate based on the measured height-direction position of the photosensitive substrate.

4. The exposure device of claim 3, wherein the controller comprises a first controller configured to adjust the height-direction position of the reflection mask based on the measured height-direction position of the reflection mask, and a second controller configured to adjust the height-direction position of the photosensitive substrate based on the measured height-direction position of the photosensitive substrate.

5. An exposure device for exposing a mask with light emitted from a light source and for transferring a pattern formed on the mask onto a photosensitive substrate, comprising:

a projection optical system;

a height-direction position measurement device configured to measure the height-direction position of the mask;

an exposure area defining member between the mask and the projection optical system configured to define a shape of the light incident on the photosensitive substrate at the time of exposure;

a movement device configured to move the exposure area defining member; and

a controller configured to control the movement device so as to fix the exposure area defining member at a first position at the time of exposure and to move the exposure area defining member to a second position where a measuring light is not obstructed by the exposure area defining member at the time of measuring the height-direction position wherein the measuring light reaches a surface of the mask which includes the area of the shape of light defined by the exposure area defining member and a peripheral region of the area of the shape of light defined by the exposure area defining member.

6. An exposure device for exposing a photosensitive substrate with a reflection mask pattern using a projection optical system, comprising:

an exposure area defining member placed between the mask and the projection optical system and configured to define a shape of a light incident on the photosensitive substrate at the time of exposure;

a mover configured to move the exposure area defining member at a height-direction measuring position, the height-direction measuring position being different from an exposure position; and

a height-direction position measurement device configured to measure the height-direction position of the mask surface, wherein a measuring light of the height-direction position measurement device reaches a surface of the mask which includes the area of the shape of light defined by the exposure area defining member and a peripheral region of the area of the shape of light defined by the exposure area defining member.

7. The exposure device of claim 6, wherein the exposure area defining member is fixed in its position at the time of exposure.

8. The exposure device of claim 6, wherein the height-direction measuring position is at a position at which the exposure area defining member does not obstruct a mechanism of a height measurement device.

9. The exposure device of claim 8, wherein the mask surface height-direction position measurement is performed by intermittently changing the relative position between the mask and the exposure area defining member.

10. The exposure device of claim 9, wherein the exposure area defining member has an opening through which exposure light can pass, and the height-direction position measurement is performed through the opening.

11. The exposure device of claim 10, wherein the mover moves a mask stage which supports the mask while measuring the height-direction position of the mask.

12. The exposure device of claim 6, wherein the exposure area defining member is a slit substrate.

13. The exposure device of claim 6, wherein the mask height-direction position measurement is performed using an optical measurement device having at least a measurement light source and a detector to detect a light flux which is emitted from the measurement light source and reflected by the mask.

14. The exposure device of claim 6, further comprising:

a measurement device configured to measure a height-direction position of a mask stage,

wherein the measured mask surface height-direction position is corrected with the measured mask stage height-direction position.

15. The exposure device of claim 6, wherein the exposure area defining member is returned to the exposure position which defines the exposure area at the time of exposure after measuring the mask surface height-direction position.

16. The exposure device of claim 6, wherein the height-direction position of the mask is corrected, at the time of exposure, based on the measured height-direction position data of the mask surface.

17. The exposure device of claim 6, wherein the height-direction position of the mask is corrected based on the measured height-direction position data of the mask surface, at the time of exposure, after measuring the mask surface height-direction position.

18. The exposure device of claim 6, wherein a height direction position of a pattern region of the mask is measured.

19. The exposure device of claim 18, wherein a height direction position of a no pattern region of the mask, which surrounds a pattern region, is measured.

20. The exposure device of claim 6, wherein the height-direction position measuring device illuminates a measurement light to a mask as the measurement light illuminates the surface of the mask obliquely.