Illumination system of a microlithographic projection exposure apparatus
AssigneeCarl Zeiss SMT GmbH
InventorMarkus Deguenther
Life of this patent
Estimating the term…
Abstract
An illumination system of a microlithographic projection exposure apparatus comprises an optical integrator having a plurality of light entrance facets and a beam deflection array of reflective or transparent beam deflecting elements. Each beam deflecting element is configured to illuminate a spot on the optical integrator at a position that is variable by changing a deflection angle produced by the beam deflecting element. The illumination system further comprises a control unit which is configured to control the beam deflection elements in such a manner that a light pattern assembled from the spots on at least one of the light entrance facets is varied in response to an input command that a field dependency of the angular irradiance distribution in a mask plane shall be modified.
Claims22
An illumination system having a pupil plane and an illumination plane, the illumination system comprising:
- an optical integrator configured to produce a plurality of secondary light sources in the pupil plane, the optical integrator comprising a plurality of light entrance facets, each of the light entrance facets being associated with one of the secondary light sources;
- a beam deflecting device comprising a beam deflection array of reflective or transparent beam deflecting elements, each beam deflecting element being configured to illuminate a spot on the light entrance facets at a position that is variable by changing a deflection angle produced by the beam deflecting element, a total area of the spots illuminated by the beam deflecting elements being at least 5 times smaller than a maximum total area of at least one of the light entrance facets;
- and
- a control unit configured to, based on a received input command, control the beam deflection elements to vary a light pattern assembled from the spots on at least one of the light entrance facets so that the illumination system produces a first angular irradiance distribution at a first portion of the illuminated field and simultaneously a second angular irradiance distribution at a second portion of the illuminated field,
- wherein the second angular irradiance distribution is different from the first angular irradiance distribution, and the illumination system is a microlithographic illumination system.
An illumination system, comprising
- an optical integrator comprising a plurality of light entrance facets;
- a beam deflection array of reflective or transparent beam deflecting elements, each beam deflecting element being configured to illuminate a spot on the optical integrator at a position that is variable by changing a deflection angle produced by the beam deflecting element;
- and
- a control unit configured to, based on a received input command, control the beam deflection elements to vary a light pattern assembled from the spots on at least one of the light entrance facets so that the illumination system produces a first angular irradiance distribution at a first portion of the illuminated field and simultaneously a second angular irradiance distribution at a second portion of the illuminated field,
- wherein the second angular irradiance distribution is different from the first angular irradiance distribution, and the illumination system is a microlithographic illumination system.
A method of operating a microlithographic illumination system comprising an optical integrator comprising a plurality of light entrance facets, the method comprising:
- i) producing light patterns on the light entrance facets of the optical integrator, the light patterns being assembled from individual spots;
- and
- ii) varying the light patterns on the light entrance facets by rearranging and/or removing and/or adding spots so that the illumination system produces a first angular irradiance distribution at a first portion of the illuminated field and simultaneously a second angular irradiance distribution at a second portion of the illuminated field,
- wherein the second angular irradiance distribution is different from the first angular irradiance distribution.
Dependencies are inferred from the claim text.