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. 27, 2003
Filed:
Nov. 03, 2000
Akihiko Isao, Saitama-ken, JP;
Susumu Kawada, Saitama-ken, JP;
Shuichiro Kanai, Saitama-ken, JP;
Nobuyuki Yoshioka, Hyogo-ken, JP;
Kazuyuki Maetoko, Hyogo-ken, JP;
Other;
Abstract
A phase-shift photo mask blank comprises a half tone phase-shift film, wherein the half tone phase-shift film consists of at least two layers and in the case of two layers, the refractive index of the upper layer of the film is smaller than that of the lower layer thereof; in the case of three layers, the refractive index of the intermediate layer is smaller than those observed for the upper and lower layers or the refractive index of the upper layer is smaller than that of an intermediate layer; in the case of at least 4 layers, the refractive index of the upper most layer is smaller than that of the layer immediately below the upper most layer. The photo mask blank permits the production of a phase-shift photo mask having a high transmittance at an exposure wavelength and a low reflectance as well as a low transmittance at a defect-inspection wavelength. The photo mask in turn permits the fabrication of a semiconductor device having a fine pattern.