Manufacturing of high performance magnetoresistive sensors

    公开(公告)号:US10859644B2

    公开(公告)日:2020-12-08

    申请号:US16359141

    申请日:2019-03-20

    Applicant: NXP B.V.

    Inventor: Mark Isler

    Abstract: A method includes depositing a hardmask layer over a magnetoresistive (MR) structural layer formed on a substrate, the hardmask layer being formed from tungsten or a tungsten-based composition. A photoresist layer is deposited over the hardmask layer and is patterned to expose a first portion of the hardmask layer. A first etch process is performed to remove the first portion of the hardmask layer and expose a second portion of the MR structural layer and a dry etch process is performed to remove the second portion of the MR structural layer and produce an MR sensor structure. Following the dry etch process, a composite structure remains that includes the MR sensor structure and a hardmask section of the hardmask layer, the hardmask section overlying the MR sensor structure. A spacer formed from a protective, dielectric material layer may additionally be formed surrounding the composite structure.

    MAGNETIC FIELD SENSOR, SYSTEM, AND METHOD FOR SPEED MEASUREMENT

    公开(公告)号:US20200333407A1

    公开(公告)日:2020-10-22

    申请号:US16388167

    申请日:2019-04-18

    Applicant: NXP B.V.

    Abstract: A sensor includes first and second magnetoresistive sensor elements configured to produce respective first and second output signals in response to an external magnetic field. The first and second magnetoresistive sensor elements form a gradient unit, each of the magnetoresistive sensor elements includes a sense layer having a vortex magnetization pattern. A processing circuit is coupled to the sensor elements and is configured to produce a differential output signal as a difference between the first and second output signals of the first and second magnetoresistive sensor elements of the gradient unit. The system includes an encoder that produces the external magnetic field and the sensor having one or more gradient units, in which the gradient units may be arranged in a second-order gradient sensing configuration.

    Stray magnetic field robust magnetic field sensor and system

    公开(公告)号:US10718825B2

    公开(公告)日:2020-07-21

    申请号:US15703102

    申请日:2017-09-13

    Applicant: NXP B.V.

    Abstract: A magnetic field sensor includes a magnetic sense element and a shield structure formed on a substrate. The shield structure fully encircles the magnetic sense element for suppressing stray magnetic fields along a first axis and a second axis, both of which are parallel to a surface of the substrate and perpendicular to one another. A magnetic field is oriented along a third axis perpendicular to the surface of the substrate, and the magnetic sense element is configured to sense a magnetic field along the first axis. A magnetic field deflection element, formed on the substrate proximate the magnetic sense element, redirects the magnetic field from the third axis into the first axis to be sensed as a measurement magnetic field by the magnetic sense element. At least two magnetic field sensors, each fully encircled by a shield structure, form a gradient unit for determining a magnetic field gradient.

    METHOD OF FORMING TUNNEL MAGNETORESISTANCE (TMR) ELEMENTS AND TMR SENSOR ELEMENT

    公开(公告)号:US20190198751A1

    公开(公告)日:2019-06-27

    申请号:US16286149

    申请日:2019-02-26

    Applicant: NXP B.V.

    CPC classification number: H01L43/08 H01L43/02 H01L43/10 H01L43/12

    Abstract: A method includes performing an ion beam etching process on a tunnel magnetoresistance (TMR) stack to remove material portions of a first magnetic layer and a tunnel barrier layer of the TMR stack. The ion beam etching process stops at a top surface of a second magnetic layer of the TMR stack. A protective layer is deposited over the TMR stack. Another etch process is performed to remove the protective layer such that a portion of the second magnetic layer is exposed from the protective layer and a spacer is formed from a remaining portion of the protective layer. The spacer surrounds sidewalls of the first magnetic layer and the tunnel barrier layer. The portion of the second magnetic layer exposed from the protective layer is removed so that a TMR sensor element remains, where the TMR sensor element includes a bottom magnet, a top magnet, and a tunnel junction.

    Magnetic field sensor with coil structure and method of fabrication

    公开(公告)号:US10330741B2

    公开(公告)日:2019-06-25

    申请号:US15719932

    申请日:2017-09-29

    Applicant: NXP B.V.

    Inventor: Mark Isler

    Abstract: A method includes forming first coil segments in an electrically conductive layer of an active silicon substrate, forming a magnetic sense element over an electrically insulating layer of the active silicon substrate, the magnetic sense element being separated from the first coil segments in the electrically conductive layer by the electrically insulating layer. A protective layer is formed over the magnetic sense element. Conductive vias are formed extending through the protective layer and the electrically insulating layer to electrically couple with the first coil segments, and second coil segments are formed over the protective layer, the second coil segments electrically coupling with the conductive vias to produce a coil structure of the first coil segments, the conductive vias, and the second coil segments, with the coil structure surrounding the magnetic sense element.

    Method of forming tunnel magnetoresistance (TMR) elements and TMR sensor element

    公开(公告)号:US10263179B2

    公开(公告)日:2019-04-16

    申请号:US15652311

    申请日:2017-07-18

    Applicant: NXP B.V.

    Abstract: A method includes performing an ion beam etching process on a tunnel magnetoresistance (TMR) stack to remove material portions of a first magnetic layer and a tunnel barrier layer of the TMR stack. The ion beam etching process stops at a top surface of a second magnetic layer of the TMR stack. A protective layer is deposited over the TMR stack. Another etch process is performed to remove the protective layer such that a portion of the second magnetic layer is exposed from the protective layer and a spacer is formed from a remaining portion of the protective layer. The spacer surrounds sidewalls of the first magnetic layer and the tunnel barrier layer. The portion of the second magnetic layer exposed from the protective layer is removed so that a TMR sensor element remains, where the TMR sensor element includes a bottom magnet, a top magnet, and a tunnel junction.

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