EUV Mask Inspection System

• US 20100149505A1
• Filed: 10/26/2009
• Published: 06/17/2010
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: SEWELL, Harry, Catey, Eric Brian, Joobeur, Adel, Shmarev, Yevgeniy Konstantinovich
• Granted Patent: US 9,046,754 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G01N 2021/95676 Masks, reticles, shadow masks
• CPC Class Codes: G03B 27/54 Lamp housings; Illuminating means
• CPC Class Codes: G03F 7/70208 Multiple illumination paths, e.g. radiation distribution devices, microlens illumination systems, multiplexers or demultiplexers for single or multiple projection systems
• CPC Class Codes: G03F 7/70275 Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems
• 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
• CPC Class Codes: G03F 7/70991 Connection with other apparatus, e.g. multiple exposure stations, particular arrangement of exposure apparatus and pre-exposure and/or post-exposure apparatus; Shared apparatus, e.g. having shared radiation source, shared mask or workpiece stage, shared base-plate; Utilities, e.g. cable, pipe or wireless arrangements for data, power, fluids or vacuum

Abstract

Disclosed are apparatuses, methods, and lithographic systems for EUV mask inspection. An EUV mask inspection system can include an EUV illumination source, an optical system, and an image sensor. The EUV illumination source can be a standalone illumination system or integrated into the lithographic system, where the EUV illumination source can be configured to illuminate an EUV radiation beam onto a target portion of a mask. The optical system can be configured to receive at least a portion of a reflected EUV radiation beam from the target portion of the mask. Further, the image sensor can be configured to detect an aerial image corresponding to the portion of the reflected EUV radiation beam. The EUV mask inspection system can also include a data analysis device configured to analyze the aerial image for mask defects.

Claims

1. A mask inspection system comprising:

an extreme ultraviolet (EUV) illumination source configured to illuminate an EUV radiation beam onto a target portion of a mask;

an optical system configured to receive at least a portion of a reflected EUV radiation beam from the target portion of the mask; and

an image sensor configured to detect an aerial image corresponding to the portion of the reflected EUV radiation beam.

2. The mask inspection system of claim 1, further comprising a data analysis device configured to analyze the aerial image for mask defects.

3. The mask inspection system of claim 2, wherein the data analysis device is configured to analyze the aerial image by at least one of:

comparing the aerial image to a previous aerial image detected by the mask inspection system;

comparing a first pattern area of the mask with a second pattern area of the mask, wherein the first pattern area is substantially identical to the second pattern area; and

comparing the aerial image to reference data stored in a design database.

4. The mask inspection system of claim 1, further comprising an inspection stage configured to support the mask during a mask inspection mode and a wafer exposure mode of operation.

5. The mask inspection system of claim 1, wherein the EUV illumination source comprises a diverter device configured to switch the EUV illumination source between a mask inspection mode and a wafer exposure mode of operation.

6. The mask inspection system of claim 1, wherein the EUV illumination source comprises a diverter device configured to substantially simultaneously illuminate the EUV radiation beam onto a mask in a patterning device of a lithographic apparatus and onto a mask in a mask inspection device.

7. The mask inspection system of claim 1, wherein the image sensor comprises a silicon charge coupled device array of sensors.

8. A method for inspecting a mask for defects, comprising:

illuminating an extreme ultraviolet (EUV) radiation beam onto a target portion of the mask;

receiving at least a portion of a reflected EUV radiation beam from the target portion of the mask; and

detecting an aerial image corresponding to the portion of the reflected EUV radiation beam.

9. The method of claim 8, further comprising analyzing the aerial image for mask defects.

10. The method of claim 9, wherein analyzing the aerial image comprises at least one of:

comparing the aerial image to a previously detected aerial image;

comparing a first pattern area of the mask with a second pattern area of the mask, wherein the first pattern area is substantially identical to the second pattern area; and

comparing the aerial image to reference data stored in a design database.

11. The method of claim 9, wherein analyzing the aerial image comprises transferring data from an image sensor to a data analysis device.

12. The method of claim 8, further comprising supporting the mask during an inspection mode and a wafer mode of operation.

13. The method of claim 8, wherein illuminating the EUV radiation beam comprises switching the EUV radiation beam between a mask inspection mode and a wafer exposure mode of operation.

14. The method of 8, wherein illuminating the EUV radiation beam comprises substantially simultaneously illuminating the EUV radiation beam onto a mask in a patterning device of a lithographic apparatus and onto a mask in a mask inspection device.

15. A lithography system, comprising:

a first illumination system configured to condition a first extreme ultraviolet (EUV) radiation beam;

a support constructed to support a first patterning device, the first patterning device configured to impart the first EUV radiation beam with a pattern in its cross-section to form a patterned radiation beam;

a substrate table constructed to hold a substrate;

a projection system configured to focus the patterned radiation beam onto the substrate; and

a mask inspection system comprising,

a second illumination system configured to illuminate a second EUV radiation beam onto a target portion of a second patterning device,

an optical system configured to receive at least a portion of a reflected EUV radiation beam from the target portion of the second patterning device, and

an image sensor configured to detect an aerial image corresponding to the portion of the reflected EUV radiation beam.

16. The lithography system of claim 15, wherein the mask inspection system further comprises a data analysis device configured to analyze the aerial image for mask defects.

17. A lithography system, comprising:

an illumination system configured to condition a first extreme ultraviolet (EUV) radiation beam and to illuminate a second EUV radiation beam onto a target portion of a first patterning device;

a support constructed to support a second patterning device, the second patterning device configured to impart the first EUV radiation beam with a pattern in its cross-section to form a patterned radiation beam;

a substrate table constructed to hold a substrate;

a projection system configured to focus the patterned radiation beam onto the substrate; and

a mask inspection system comprising,

an optical system configured to receive at least a portion of a reflected EUV radiation beam from the target portion of the first patterning device, and

an image sensor configured to detect an aerial image corresponding to the portion of the reflected EUV radiation beam.

18. The lithography system of claim 17, wherein the mask inspection system further comprises a data analysis device configured to analyze the aerial image for mask defects.

19. The lithography system of claim 17, wherein the illumination system is configured to illuminate the second EUV radiation beam onto the target portion of the first patterning device, while at least one of the substrate is being replaced with a second substrate that requires patterning and a change in scan direction is required when patterning the substrate with the first EUV radiation beam.

20. The lithography system of claim 17, wherein:

the mask inspection system further comprises a second support constructed to support the first patterning device; and

the lithography system is configured to transfer the first patterning device to the support constructed to support the second patterning device such that the first patterning device is used as part of a lithographic patterning process.