Microlithography projection-exposure masks, and methods and apparatus employing same
US5851707A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1997 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Jul 24, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70466
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods and apparatus are disclosed for microlithographically exposing a photosensitive substrate comprising single-exposure areas and multiple-exposure areas. After exposing the substrate, line widths in the single-exposure areas are substantially the same as line widths in the multiple-exposure areas. Also disclosed are masks comprising a first mask pattern used to expose the single-exposure areas once and a plurality of other mask patterns for exposing the multiple-exposure areas a predetermined number of times. Each of the other mask patterns allows a lower intensity of illumination light flux to be distributed to the multiple-exposure areas per exposure of the substrate than allowed by the first mask pattern. Consequently, the average intensity of illumination-light flux distributed to the single-exposure area after one exposure is substantially equal to the average intensity of illumination-light flux distributed to the multiple-exposure areas after a predetermined number of exposures of such areas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.