Projectin exposure apparatus
US5627626A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | May 6, 1997 |
| Priority date | — |
| Expiry date | Jun 6, 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. A special stop 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 so that intensities of both peripheral and central portions are larger than an intensity of an intermediate portion. In addition, the apparatus includes a halftone mask which allows an amplitude transmittance T of the translucent film and an amplitude transmittance T0 of the light-transmitting substrate to satisfy 0.01.times.TO<or=T<or=0.30.times.TO. The phase difference between light passing through the light-transmitting substrate is represented by 180.times.(2n+1)+or -30 (degree) (where n is an integer).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.