System and method for improving line width control in a lithography device using an illumination system having pre-numerical aperture control
US6784976B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2002 |
| Grant date | Aug 31, 2004 |
| Priority date | — |
| Expiry date | Apr 23, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70625
- WIPO fieldOptics
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.