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:
Dec. 23, 1997
Filed:
Jun. 28, 1995
Norio Hasegawa, Hinode-machi, JP;
Tsuneo Terasawa, Ome, JP;
Hiroshi Fukuda, Kodaira, JP;
Katsuya Hayano, Hachioji, JP;
Akira Imai, Hachioji, JP;
Akemi Moniwa, Hannou, JP;
Shinji Okazaki, Urawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A photomask used for printing a mask pattern by projection optics, in which a main pattern formed of a transparent area is provided in a semitransparent area formed of a semitransparent film and a phase shifter, and the phase angles of light beams passing through respective areas are different from each other substantially by 180.degree.. The photomask is intended to prevent a reduction in a production yield due to a resolution failure of the photomask, and to prevent generation of an unnecessary projected image. In this photomask, a transparent auxiliary pattern having the same phase angle of light as that of the transparent area is disposed around a main pattern formed of the transparent area, and a distance D between the center or a desired center line of the main pattern and that of the auxiliary pattern satisfies the relationship of D=b.lambda./NAm , where NAm is a mask-side numerical aperture of a projection lens, .lambda. is a wavelength of exposure light, and <b> is a coefficient in the range of 1.35<b.ltoreq.1.9.