Method of phase shift lithography
US5766829A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1995 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | May 30, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70466
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of phase shift lithography includes forming a chromeless phase shift reticle with a pattern of parallel, spaced phase shifters. The phase shift reticle is placed between an exposure source (e.g., UV light) and a substrate having a layer resist formed thereon. Following an initial exposure, the phase shift reticle is rotated and the substrate is exposed a second time. The resist is then developed to form features in areas of resist that have not been exposed. These areas correspond to the projected points of intersection of the phase shifters. Using a positive tone resist, solid resist features are formed. These solid features can be used as mask blocks for etching the substrate to form field emitter sites for a field emission display. Using a negative tone resist, open areas are formed in the resist and can be used to deposit a material on the substrate such as a contacts for a semiconductor structure. The method of the invention can also be implemented using two different reticles with intersecting patterns or using a single reticle having intersecting phase shift areas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.