Method of fabrication of inverted phase-shifted reticle
US5300379A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | Aug 21, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A phase-shifted reticle with patterns proximate each other having inverted phases for the features and phase-shifting elements, and methods of fabricating the reticle, are disclosed. In a preferred embodiment, the inverted reticle is used to form an array of closely spaced contact or via openings. For a first pattern on the reticle, the feature will be the 0.degree. phase and the phase-shifting rim surrounding that feature will be the 180.degree. phase. All patterns surrounding the first pattern have phase-shifting rims of the 0.degree. phase and features of the 180.degree. phase. In this way, each pattern can form below conventional resolution features in the resist. Additionally, there will not be exposure of the regions between the closely spaced features since radiation transmitted through the closely spaced phase-shifting rims of the two patterns is 180.degree. out of phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.