The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 06, 1997
Filed:
Jun. 06, 1995
Soichi Inoue, Yokohama, JP;
Tadahito Fujisawa, Tokyo, JP;
Shin-ichi Ito, Yokohama, JP;
Takashi Sato, Yokohama, JP;
Shuichi Tamamushi, Kawasaki, JP;
Keiji Horioka, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
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).