International Business Machines Corporation

Nickolas Joseph Mazzeo

Jeffrey P Gambino

George G Gifford

Edward Kobeda

David A Thompson

The present invention provides a method for fabricating tungsten local interconnections in high density CMOS circuits, and also provides high density CMOS circuits having local interconnections formed of tungsten. Pursuant to the method, an etch stop layer of chromium is initially deposited on the circuit elements of the CMOS silicon substrate. Next, a conductive layer of tungsten is non-selectively deposited on the chromium layer. A photoresist mask is then lithographically patterned over the tungsten layer. The tungsten layer is then etched down to, and stopping at, the chromium layer, after which the photoresist mask is stripped. The stripping preferably uses a low temperature plasma etch in O.sub.2 at a temperature of less than 100.degree. C. Finally, a directional O.sub.2 reactive ion etch is used to remove the chromium layer selectively to the silicon substrate. Borderless contacts are formed with the aid of the chromium etch stop layer beneath the tungsten local interconnection layer. The method of integration of this approach results in anisotropic metal lines patterned over topography using a standard photoresist mask. This approach also allows partial overlap of contacts to reduce device dimensions, and thereby results in improved density and performance.

Method for fabricating Tungsten local interconnections in high density

Method for fabricating tungsten local interconnections in high density

A thin film magnetoresistive sensor of NiFeCo is juxtaposed with a saturable thin film shield of more highly permeable NiFe material. The curve depicting change of resistance of the sensor as a function of applied magnetic field is flattened, permitting the sensor to provide a magnetic switch, such as a keyboard transducer, a sensor of current through wires, a magnetic bubble detector and a remote control scanning sensor in a recording head. The scanner involves a stepped arrangement for providing different levels of sensitivity for adjacent sections of the magnetoresistive sensor.

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Mahopac, NY, United States of America

Nickolas Joseph Mazzeo