Electron beam lithography system
US5466904A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1993 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Dec 23, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31788
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
An electron beam system for direct writing applications combining the parallel throughput of a projection system and the stitching capability of a probe-forming system employs an electron gun to illuminate an initial aperture uniformly, a first set of controllable deflectors to scan the beam over the reticle parallel to the system axis, impressing the pattern of a subfield of the reticle in each exposure, in which a first variable axis lens focuses an image of the initial aperture on the reticle, a second variable axis lens collimates the patterned beam, a second set of controllable deflectors to bring the beam back to an appropriate position above the wafer, and a third variable axis lens to focus an image of the reticle subfield on the wafer, together with correction elements to apply aberration corrections that may vary with each subfield, thereby providing high throughput from the use of parallel processing of the order of 10.sup.7 pixels per subfield with the low aberration feature of the variable axis lens and the ability to tailor location-dependent corrections that are associated with gaussian systems that stitch the image pixel by pixel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.