US 2002/0153495 A1 · Magnetically shielded enclosures for housing charged-particle-beam systems

Abstract

Magnetically shielded enclosures are provided that house charged-particle-beam (CPB) systems (e.g., CPB microlithography apparatus) having active-canceler coils. The enclosures have outer walls comprised of anisotropic magnetic materials or of magnetically divided plates. The magnetically divided plates may be made of Permalloy or other similar material. The anisotropic or magnetically divided outer walls may be configured to align the external magnetic field in the direction of the magnetic field produced by the active canceler. Thus, controlling the electrical current in the active-canceler coils to cancel the external magnetic field is simplified, even if the CPB microlithography apparatus has a complex shape or is in an environment with a non-uniform magnetic field.

Claims19

Dependent claims

A charged-particle-beam (CPB) system, comprising:

a CPB optical system;
an active-canceler coil set situated relative to the CPB optical system, the active-canceler coil set comprising at least one coil pair that is individually electrically energizable to produce a respective magnetic field having a direction and magnitude sufficient for canceling at least a portion of an external magnetic field that otherwise would extend to the CPB optical system;
and
a shielded enclosure situated externally relative to the active-canceler coil set, the shielded enclosure comprising at least one outer wall comprised of an anisotropic magnetic material.

1 more element

Dependencies are inferred from the claim text.

Magnetically shielded enclosures for housing charged-particle-beam systems

Life of this patent

Magnetically shielded enclosures for housing charged-particle-beam systems

Life of this patent

Abstract

Claims19