Device manufacturing method, orientation determination method and lithographic apparatus

• US 20050117794A1
• Filed: 09/08/2004
• Published: 06/02/2005
• Est. Priority Date: 09/22/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Visser, Raimond, Kuipers, Leo Wilhelmus Maria
• Granted Patent: US 8,064,730 B2
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G03F 9/7003 Alignment type or strategy, e.g. leveling, global alignment
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method to determine a rotation of a substrate with respect to the patterning device without using a reference mark on the substrate is presented. At least two structures having corresponding features and present on the substrate, e.g. previously projected patterns, are imaged with a known position with respect to a measurement coordinate system. A distance vector between the at least two structures is determined. From the distance vector, a rotation angle is calculated. In an embodiment of the invention, there is provided a method to estimate a position of the substrate from the acquired image(s). A position is measured and used as a reference position for subsequent substrates of which the rotation angle is to be determined.

Claims

1. A device manufacturing method comprising:

patterning a beam of radiation using a patterning device;

determining an orientation of a substrate;

aligning the substrate and the patterning device according to the orientation of the substrate; and

projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material disposed on the substrate;

wherein determining the orientation of the substrate includes determining a rotation of the substrate by;

determining a distance vector in a measurement coordinate system between at least two structures disposed on said substrate, said at least two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system;

decomposing the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; and

calculating a rotation of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance.

2. The method of claim 1, wherein the at least two structures have an arbitrary geometry.

3. The method of claim 1, wherein the distance vector is determined from at least one image of the at least two structures, the at least one image being acquired by an imaging device.

4. The method of claim 3, further comprising acquiring an image of each of the at least two structures separately.

5. The method of claim 4, further comprising rotating the substrate and displacing the imaging device essentially along a radius of the substrate to obtain a separate image of each structure.

6. The method of claim 3, wherein determination said distance vector includes finding a maximum correlation between images of the structures.

7. The method of claim 1, wherein the pattern coordinate system is defined by a recurrence grid of a recurrent pattern.

8. The method of claim 1, wherein the at least two structures are asymmetrical.

9. The method of claim 1, further comprising determining an orientation of another substrate by calculating a translation of the pattern coordinate system in relation to the measurement coordinate system, said calculating including:

determining a position of the first substrate using a position measurement system;

determining a rotation of the other substrate using same structures, having corresponding features, as the at least two structures used for determining the rotation of the first substrate;

determining relative structure translation vectors between the at least two structures of the first substrate and of the other substrate; and

determining a position of the other substrate using the measured position of the first substrate as a reference position and the structure translation vectors between the structures of the first substrate and of the other substrate as a displacement from the reference position.

10. The method of claim 9, wherein the reference position is amended after each determination of the position of each other substrate by the position measurement system.

11. A method for determining a rotation of an object comprising:

determining a distance vector in a measurement coordinate system between at least two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system;

decomposing the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; and

calculating a rotation of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance.

12. A lithographic apparatus comprising:

an illumination system configured to condition a beam of radiation;

a support structure configured to support a patterning device, the patterning device serving to pattern the beam of radiation according to a desired pattern;

a substrate table configured to hold a substrate;

a projection system configured to project the patterned beam of radiation onto a target portion of the substrate;

and an alignment system configured to (a) determine a distance vector in a measurement coordinate system between at least two structures disposed on said substrate, said at least two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system, (b) decompose the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; and

(c) calculate a rotation of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance to align said substrate and said patterning device.

13. A method for aligning a substrate in a lithographic apparatus comprising:

acquiring images of a first and a second corresponding structure to determine a first distance vector between the first and the second corresponding structure in a measurement coordinate system of the lithographic apparatus, the first and second corresponding structure being located on two adjacent target portions of the substrate;

determining a second distance vector between the first and second corresponding structure in a pattern coordinate system; and

determining a rotation angle of the pattern coordinate system relative to the measurement coordinate system using the first and the second distance vector.

14. The method of claim 13, wherein the images of the first and second corresponding structure are acquired with a CCD-camera.

15. The method of claim 13, wherein the second distance vector corresponds to the incremental exposure step of the lithographic apparatus.

16. The method of claim 13, further comprising aligning the substrate based on the rotation angle.