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US 7,253,881 B2Granted
Methods and systems for lithographic gray scaling
AssigneeASML Netherlands B.V.
InventorsJoeri Lof, Pieter Willem Herman De Jager, Joannes Theodor De Smit
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Abstract
Improved gray scaling imaging methods and systems include a group of elements within an array of individually controllable elements that project a part of a radiation beam onto a lens in an array of microlenses, and are individually controllable so that any number of the individually controllable elements may be switched on or off to generate a gray scale.
Claims20
A lithographic apparatus comprising:
- an illumination system that conditions a radiation beam;
- an array of individually controllable elements that modulates a cross-section of the radiation beam;
- a substrate table that supports a substrate;
- a projection system that projects the modulated radiation beam onto a target portion of the substrate, the projection system including an array of focusing elements arranged in a plane such that each focusing element transmits a different part of the radiation beam onto a spot on the substrate;
- and
- a controller that controls elements within a group of a plurality of the individually controllable elements to direct part of the modulated radiation beam through a respective focusing element in the array of focusing elements, such that an exposure moment of the focusing element is maximized, wherein the exposure moment is defined by one of (a) the area of the focusing element traversed by the radiation beam, and (b) the area of the focusing element traversed by the radiation beam multiplied by the distance from the center of the focusing element summed over the focusing element.
3 more elements
A lithographic method, comprising:
- outputting a radiation beam using an illumination system;
- modulating a cross section of the radiation beam using an array of individually controllable elements;
- providing an array of focusing elements arranged in a plane such that each focusing element transmits a different part of the radiation beam onto a spot on a substrate, a group of a plurality of the individually controllable elements selectively directing a part of the modulated radiation beam onto a single focusing element in the array of focusing elements;
- controlling the group of the plurality of individually controllable elements used to direct part of the modulated radiation beam through the single focusing element to maximize an exposure moment of the single focusing element, wherein the exposure moment of the single focusing element is defined by one of (a) the area of the single focusing element traversed by the radiation beam, and (b) the area of the single focusing element traversed by the radiation beam multiplied by the distance from the center of the single focusing element summed over the single focusing element;
- and
- projecting the modulated beam of radiation onto a target portion of the substrate.
3 more elements
A lithographic method, comprising:
- receiving a beam of radiation at an array of individually controllable elements;
- directing portions of the beam of radiation from corresponding groups of the individually controllable elements to a substrate through corresponding focusing elements;
- and
- selectively controlling elements within the groups of a plurality of the individually controllable elements to maximize an exposure moment of each corresponding focusing element, wherein the exposure moment of a particular corresponding focusing element is defined by one of (a) the area of the particular focusing element traversed by the beam of radiation, and (b) the area of the particular focusing element traversed by the beam of radiation multiplied by the distance from the center of the particular focusing element summed over the particular focusing element.
1 more element
Dependencies are inferred from the claim text.