US 9,543,067 B2Granted

Magnetic pre-conditioning of magnetic sensors

AssigneeNXP USA, Inc.

InventorsCarlos M. Acuna, Mohammad A. Faruque, Kevin R. Fugate, Todd D. Hoffmann, Paige M. Holm, Peter T. Jones, Rigoberto Lopez, Jr., William D. McWhorter

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

Methods, systems and apparatus are provided to apply a magnetic pre-conditioning to magnetic tunneling junction (MTJ) sensors and other micro-magnetic devices after fabrication but before testing, trimming or other subsequent processing. The fabricated sensor device is passed through a magnetic field that has a known direction and orientation relative to the device so that the device is placed into a known state prior to final testing and trimming. Various embodiments allow the field to be applied in situ by a permanent magnet or electromagnet as the devices are being processed by a conventional device handler or similar processing system.

Claims18

Dependent claims

A method executable by a handler apparatus to process a fabricated sensor device that comprises a magnetic sensing element and a flux guide aligned to direct magnetic flux toward the magnetic sensing element, the method comprising:

passing the fabricated sensor device through an externally applied magnetic field applied by an external magnetic field source that is outside of the fabricated sensor device by the handler apparatus, the externally applied magnetic field having a component aligned along a long axis of the flux guide, the component of the externally applied magnetic field having a magnitude along the long axis of the flux guide sufficient to place the flux guide of the fabricated sensor device into a known magnetic state;
prior to passing the fabricated sensor device through the externally applied magnetic field, the handler apparatus aligning the fabricated sensor device to the externally applied magnetic field so that the long axis of the flux guide is aligned to the component of the externally applied magnetic field while the fabricated sensor device passes through the externally applied magnetic field to thereby magnetically pre-condition the fabricated sensor device prior to testing and operation of the fabricated sensor device;
and
after passing the fabricated sensor device through the externally applied magnetic field, the handler apparatus providing the fabricated and pre-conditioned sensor device for subsequent testing and operation of the fabricated sensor device.

1 more element

A handler system for processing sensing devices, each sensing device comprising a magnetic sensing element and a flux guide aligned to direct magnetic flux toward the magnetic sensing element, the handler system comprising:

a supply source configured to receive the sensing devices after fabrication of the sensing devices;
a movable member configured to obtain the sensing devices from the supply source, to align the sensing device to an externally-applied magnetic field prior to testing and operation of the sensing device so that at least a component of the externally applied magnetic field is aligned along a long axis of the flux guide, and to move the sensing devices along a path from the supply source toward at least one test station;
and
a magnetic field source external to the sensing devices that is located proximate to the path of the sensing devices to thereby apply the externally applied magnetic field to the aligned sensing devices as the movable member moves the sensing devices along the path toward the at least one test station to thereby magnetically pre-condition the sensing devices prior to testing and operation of the sensing devices.

1 more element

A magnetic yoke apparatus for providing a magnetic field to a sensing device that comprises a magnetic sensing element and a flux guide having a long axis aligned to direct magnetic flux toward the magnetic sensing element, the magnetic yoke apparatus comprising:

a crosspiece member comprising a region configured to accept the sensing device;
and
a magnet disposed on the crosspiece member to thereby produce an externally applied magnetic field in the region configured to accept the sensing device, wherein the magnet is external to the sensing device and is configured to apply the externally applied magnetic field as an externally-applied field that is aligned along the long axis of the sensing device as the sensing device is placed in the region configured to accept the sensing device and to thereby magnetically pre-condition the sensing device prior to testing and operation of the sensing device.

Dependencies are inferred from the claim text.

Facts

Application: 14/135,956Filed 20 Dec 2013
Published: US 2015/0179325 A125 Jun 2015
Granted: 10 Jan 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H01F 7/0294
Magnetic circuits with PM for magnetic field generation: detection, inspection, magnetic treatment
G01R 1/0408
Housings; Supporting members; Arrangements of terminals: test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets
G01R 31/315
Contactless testing: by inductive methods
H01F
Magnets