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:
Mar. 18, 2003
Filed:
Oct. 28, 1999
Kazuo Tanaka, Sakata, JP;
Takashi Kumagai, Chino, JP;
Junichi Karasawa, Tatsuno-machi, JP;
Kunio Watanabe, Sakata, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A semiconductor memory device (SRAM) comprises memory cells, each of which includes two load transistors, two driver transistors and two transfer transistors. The SRAM cell includes a semiconductor substrate in which the transistors are formed, a first interlayer dielectric formed on the semiconductor substrate, first contact portions formed in the first interlayer dielectric and first wiring layers (node wiring layers and pad layers) formed on the first interlayer dielectric. The first contact portions and the first wiring layers include metal layers made of refractory metal and a refractory metal nitride layers. This semiconductor memory device of the present invention is capable of enhancing an integration degree of wiring layers and achieving a microfabrication.