Electron beam column using high numerical aperture photocathode source illumination
US6448568B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1999 |
| Grant date | Sep 10, 2002 |
| Priority date | — |
| Expiry date | Jul 30, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3175
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lithography apparatus including both a laser beam source and an electron beam column, where the electron beam column has a support(in one embodiment a window in the column housing) having an index of refraction n. The support, having a photocathode source material disposed on its remote surface, is located in some embodiments such that the internal angle of the incident laser beam is &thgr; with respect to a line perpendicular to the remote surface. The numerical aperture of the substrate(equal to nsin &thgr;) is greater than one in one embodiment, resulting in a high resolution spot size diameter incident on the photocathode source material at the remote surface. Incident energy from the laser beam thereby emits a corresponding high resolution electron beam from the photocathode source material. Electromagnetic lens components are disposed downstream in the electron beam column to demagnify the electron beam. This apparatus allows the continuously decreasing minimum feature dimension sizes for semiconductor electron beam lithography.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.