MAGNETORESISTANT ELEMENT AND MANUFACTURING PROCESS THEREOF

摘要

A magnetoresistant element used for magnetic sensors etc., which is manufactured by so forming a thin film of a ferromagnetoresistant element as to be superimposed on the end part of an aluminum wiring metal provided on a substrate, by connecting electrically the thin film of the ferromagnetoresistant element to the aluminum wiring metal, and by subjecting both of them to a vacuum heat treatment at a temperature of 350-450 DEG C. By the vacuum heat treatment, an Ni-Al alloy is formed in the connection part of the aluminum wiring metal and the thin film of the ferromagnetoresistant element. Subsequently, even if by a plasma CVD process, on the surface of the alloy, formed is a surface protective film made of silicon nitride, the surface of the aluminum wiring metal on the connection part is prevented from the being nitrided by virtue of the Ni-Al alloy. Therefore, the surface of the alloy can be protected by silicon nitride excelling in moisture resistance, and in addition to this, the resistance of the junction of the thin film of the ferromagnetoresistant element and the wiring metal can be suppressed from increasing accompanied by the formation of this surface protective film. Also, to suppress this increase of the junction resistance, it is allowable that the thin film of the ferromagnetoresistant element and the aluminum wiring metal are connected by another conductor metal. As the conductor metal, TiW, TiN, Ti, Zr, etc. are preferable. Also, a second aluminum wiring metal is usable, when the conductor metal is provided on the upper layers side of the thin film of the ferromagnetoresistant element. Further, usable is the surface protective film of a multilayer type, whose lower layer side is a film containing no nitrogen, such as a silicon oxide film, and whose upper layer side is a surface protective film made of silicon nitride.