Projection exposure apparatus
US5621498A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1995 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | Mar 28, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70333
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection exposure apparatus is constituted by a first focusing optical system for focusing light from a mercury-vapor lamp as a light source, a uniforming optical system for uniforming the focused light, a second focusing optical system for focusing the uniformed light and radiating the light onto a reticle mask, and a projection optical system for projecting the light, transmitted through the reticle, onto a wafer. The apparatus is designed to project/expose a predetermined mask pattern, formed on the mask, onto the wafer through the projection optical system. A special stop (i.e., a four-eye filter) is arranged as a secondary source for uniformly illuminating the mask. The special stop serves to set an intensity distribution within the exit plane of the secondary source such that intensities in four regions quadruple-symmetrical about the optical axis of the secondary source and decentered therefrom are higher than intensities in other regions. A translucent pattern is formed as the mask on a light-transmitting substrate. The phase difference between light passing through the translucent film and light passing through the light-transmitting substrate is represented by 180.tim…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.