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:
Nov. 24, 1998
Filed:
Jan. 24, 1997
Satoshi Nakagawa, Toyama, JP;
Toyoji Ito, Shiga, JP;
Yoji Bito, Toyama, JP;
Yoshihisa Nagano, Osaka, JP;
Matsushita Electronics Corporation, Osaka, JP;
Abstract
A device insulating film, a lower-layer platinum film, a ferroelectric film, an upper-layer platinum film, and a titanium film are sequentially formed on a semiconductor substrate in this order. On the titanium film, a photoresist mask is further formed in a desired pattern. The thickness of the titanium film is adjusted to be 1/10 or more of the total thickness of a multilayer film consisting of the upper-layer platinum film, the ferroelectric film, and the lower-layer platinum film. The titanium film is then subjected to dry etching and the photoresist film is removed by ashing process. The titanium film thus patterned is used as a mask in etching the upper-layer platinum film, the ferroelectric film, and the lower-layer platinum film by a dry-etching method using a plasma of a gas mixture of chlorine and oxygen in which the volume concentration of oxygen gas is adjusted to be 40%. During the dry-etching process, the titanium film is oxidized to provide a high etching selectivity. Subsequently, the titanium film is removed by dry etching using a plasma of chlorine gas.