Generic phase shift masks
US6479196B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Sep 6, 2001 |
| Grant date | Nov 12, 2002 |
| Priority date | — |
| Expiry date | Sep 6, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/26
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180° shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.