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:
Oct. 08, 2002
Filed:
Mar. 27, 2001
Hideki Takeuchi, Tokyo, JP;
Hirohiko Izumi, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
In a semiconductor storage device, an access transistor, which has a gate electrode and a pair of impurity diffusion layers, is formed at a device activation region defined by a device isolation structure of a semiconductor substrate. A first insulating film, which has a first contact hole for exposing a portion of the surface of one of the pair of impurity diffusion layers, is formed over the access transistor. A protective film, which has a second contact hole formed on the first contact hole, is formed on the first insulating film. A second insulating film is formed on the side wall faces of the first and second contact holes. A memory capacitor has a lower electrode and an upper part electrode which are opposed each other and are capacitive-coupled through a dielectric film. The lower electrode is filled inside the first and second contact holes to be formed in an island-like shape on the first insulating film through the protective film so as to be electrically connected with the one of the pair of impurity diffusion layers. Each of the first and second contact holes has a diameter which is made smaller by an existence of the second insulating film than a minimum dimension determined by an exposure limit in a photolithography.