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:
Jan. 06, 2009
Filed:
Jul. 23, 2007
Yasuhiro Kanamaru, Yokohama, JP;
Keiji Hanzawa, Mito, JP;
Yasuhiro Kanamaru, Yokohama, JP;
Keiji Hanzawa, Mito, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An object of the invention is to realize a thermal gas flow sensor capable of reducing time fluctuation of a heating resistor. A heating resistorand thermometric resistorsandare formed on a surface of a thin-wall portion. Electrode drawn wirestoand pad portionstoare formed so as to draw signal lines from the heating resistorand the thermometric resistorsand. Contact portionstoare formed to come in contact with the heating resistor, the thermometric resistorsand, and the electrode drawn wiresto. The heating resistorand the thermometric resistorsandare covered with protective films, andand insulating filmsand. The protective filmsandare formed of a dense film formed of nitride or the like. A part coming in contact with a drawn wire portionand the heating resistoris covered with a contact barrier metal film(titanium-based electrical conductor such as titanium nitride, titanium tungsten, and titanium). The titanium-based electrical conductor is a dense film and resistant to hydrogen. Therefore, it is possible to reduce a time fluctuation of the heating resistor.