US 6,784,976 B2 · System and method for improving line width control in a lithography device using an illumination system having pre-numerical aperture control

Abstract

A system and method for improving line width control in a lithography device are presented. Electromagnetic energy is emitted from an illumination source and passed through illumination optics. The illumination optics include a partial coherence adjuster having a first and second optical element. The first optical element is used for changing the partial coherence of incident electromagnetic energy in a predetermined manner to compensate for horizontal and vertical line biases of the lithography device. The second optical element is used for changing the angular distribution of electromagnetic energy incident upon the first optical element. Together, the two optical elements are used to vary the partial coherence of the electromagnetic energy emitted by the illumination source, as a function of illumination field position, and improve line width control. Adjustment of the second optical element allows for correction of time-dependant line width variances.

Claims33

Dependent claims

A lithography system, comprising:

an illumination source;
an illumination optics module that receives electromagnetic energy emitted by said illumination source, said illumination optics module having a partial coherence adjuster module comprising:
a first optical element that changes the partial coherence of incident electromagnetic energy in a predetermined manner to compensate for horizontal and vertical line biases, and
a second optical element that changes the angular distribution of electromagnetic energy incident upon said first optical element;
a reticle stage positioned adjacent to said illumination optics module, wherein electromagnetic energy exiting said illumination optics module will illuminate a portion of a reticle held by said reticle stage;
a wafer stage;
and
a projection optics module having an image plane proximate to said wafer stage, said projection optics module positioned adjacent to said reticle stage and adjacent to said wafer stage, wherein electromagnetic energy passing through the reticle held by said reticle stage will enter said projection optics module and be imaged by said projection optics module on a photosensitive substrate on a wafer held by said stage.

5 more elements

Dependencies are inferred from the claim text.

System and method for improving line width control in a lithography device using an illumination system having pre-numerical aperture control

Life of this patent

System and method for improving line width control in a lithography device using an illumination system having pre-numerical aperture control

Life of this patent

Abstract

Claims33