Modification of a projection imaging system with a non-circular aperture and a method thereof
US6541750B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 17, 2000 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Mar 17, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70441
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A imaging tool for use with a mask with features oriented along at least an x-axis or a y-axis where the x-axis extends in directions substantially perpendicular to the directions of the y-axis. The tool has a condenser lens and an objective lens. The condenser lens has a condenser aperture with four-sides and four comers that are located in a condenser lens pupil plane. The sides of the condenser aperture are oriented in substantially the same direction as either the x-axis or the y-axis. The condenser lens is positioned to place at least a portion of any illumination on the mask and then into an objective lens pupil plane of the objective lens. At least one of the comers of the condenser aperture in the condenser plate may have a substantially rounded shape. Additionally, the mask may have at least one artifact added to at least one comer of the features for optical proximity correction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.