LIGHT SOURCE

Abstract

At least one exemplary embodiment is directed to a light source which includes a plasma generator configured to generate plasma, a mirror configured to reflect light that is produced by the plasma, a plurality of plates provided between the plasma and the mirror and arranged radially around an axis passing through a light emission center, and a magnetic-field generator for generating a magnetic line of force between the plasma and the mirror so that trajectories of charged particles scattering from the plasma are curved toward the plates.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of a light source according to a first exemplary embodiment of the present invention.

FIG. 2 is an explanatory view showing trajectories of debris particles in the first exemplary embodiment.

FIG. 3 is an explanatory view showing a modification of the first exemplary embodiment.

FIGS. 4A and 4B are schematic structural views showing a second exemplary embodiment of the present invention.

FIG. 5 is an explanatory view showing calculation of the magnetic flux density for capturing debris particles.

FIG. 6 is an explanatory view showing calculation of the magnetic flux density for capturing debris particles.

FIG. 7 is an explanatory view showing the arrangement of magnets in the first exemplary embodiment.

FIG. 8 is an explanatory view showing the arrangement of the magnets in the first exemplary embodiment.

FIGS. 9A and 9B are explanatory views showing the direction of a magnetic line of force in the first exemplary embodiment.

FIG. 10 is an explanatory view of a related art.

FIG. 11 is an explanatory view of another related art.

FIG. 12 is a schematic structural view of an exposure apparatus.

FIG. 13 is a flowchart of a semiconductor-device manufacturing process.

FIG. 14 is a detailed flowchart of a wafer process in the process shown in FIG. 13.

Claims

1. A light source comprising: a plasma generator configured to generate a plasma;a mirror configured to reflect light that is emitted from the plasma;a plurality of plates provided between the plasma and the mirror and arranged radially around an axis passing through a light emission center; anda magnetic-field generator configured to generate a magnetic line of force located between the plasma and the mirror, where a component of the magnetic line of force curves the trajectories of charged particles from the plasma toward the plates.

2. The light source according to claim 1, wherein the component is perpendicular to a radiating direction from the light emission center in a plane including the axis.

3. The light source according to claim 2, wherein the magnetic line of force is formed in a space between at least two of the plurality of plates.

4. The light source according to claim 2, wherein the magnetic line of force is formed in a space between a space between at least two of the plurality of plates, and the plasma.

5. The light source according to claim 1, wherein the magnetic-field generator includes a pair of permanent magnets opposing each other along the axis.

6. The light source according to claim 1, wherein the magnetic-field generator includes a plurality of permanent magnets, andwherein one of the permanent magnets is disposed on the optical axis of the mirror, and the other permanent magnets are arranged radially around the optical axis.

7. An exposure apparatus comprising: a light source according to claim 1;an illumination optical system for illuminating a reticle having a pattern with light from the light source; anda projection optical system for projecting the pattern onto a wafer.

8. A device manufacturing method comprising the steps of: applying a resist on a wafer;exposing the wafer with a pattern by an exposure apparatus according to claim 7; anddeveloping the exposed wafer.

9. The light source according to claim 1, wherein at least one plate has an end nearer to the light emission center that has a distance r1 from the light emission center, and the at least one plate has an end the furthest from the light emission center that has a distance r2 from the light emission center, where θ is the angle between the intersection of at least two plates, where the distance from r2 to r1 has been predetermined so that a chosen radius of curvature R of a target charged particle emitted from the plasma has a radius of curvature R, that satisfies: r1/8<R<4√{square root over (r12−r1r2 cos θ+r22/4)}

10. The light source according to claim 1, wherein at least one plate has an end nearer to the light emission center that has a distance r1 from the light emission center, and the at least one plate has an end the furthest from the light emission center that has a distance r2 from the light emission center, where θ is the angle between the intersection of at least two plates, where the distance from r2 to r1 has been predetermined so that a chosen radius of curvature R of a target charged particle emitted from the plasma has a radius of curvature R, that satisfies: (1−cos θ)r1/4 sin θ<R<2(r12+r22−2r1r2 cos θ)/r2 sin θ