IP Library › Granted Patent US 10,162,016
Granted Patent B2
US 10,162,016 · App. 15/064,579 · Granted Dec 25, 2018

Reduction of magnetic sensor component variation due to magnetic materials through the application of magnetic field

Inventors: Ann Margaret Gabrys (Woodside, CA); Dok Won Lee (Mountain View, CA)
Assignee: TEXAS INSTRUMENTS INCORPORATED
G01R33/0017G01R33/04G01R33/07G01R33/09
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Quick Facts
Patent No.
US 10,162,016
App. No.
15/064,579
Granted
Dec 25, 2018
Kind
B2
Abstract

A microelectronic device, possibly a packaged microelectronic device, contains a magnetic sensor component and magnetizable structural features. Magnetic moments of the magnetizable structural features are aligned parallel to each other. The microelectronic device is formed by applying a magnetic field so as to align magnetic moments of the magnetizable structural features with the applied magnetic field. Application of the magnetic field is subsequently discontinued. The magnetic moments of the magnetizable structural features remain aligned parallel to each other after the applied magnetic field is discontinued.

Claims (31)

1. A method, comprising:

applying a magnetic field greater than a stray magnetic field to magnetizable structural features of a microelectronic device that is part of a substrate wafer with other microelectronic devices, wherein the magnetizable structural features are separate from a magnetic sensor component of the microelectronic device, for a predetermined duration to align magnetic moments of the magnetizable structural features parallel to the magnetic field, wherein the magnetizable structural features comprise bond pads and wherein the magnetic sensor component includes a fluxgate magnetometer core; and

discontinuing application of the magnetic field after the predetermined duration.

2. The method of claim 1 , wherein the magnetic field is at least 10 millitesla (mT).

3. The method of claim 1 , wherein the magnetizable material comprises nickel.

4. The method of claim 1 , wherein the magnetic field is oriented parallel to a top surface of the substrate.

5. The method of claim 1 , wherein the magnetic sensor component includes a magnetoresistive sensor.

6. The method of claim 1 , wherein the magnetic field is oriented perpendicular to a field measurement axis of the magnetic sensor component.

7. The method of claim 1 , wherein the magnetic field is applied using a Halbach device.

8. The method of claim 1 , wherein the magnetic field is applied using electrical currents to generate the magnetic field.

9. The method of claim 8 , wherein the magnetic field is applied using Helmholtz coils.

10. A method, comprising:

applying a magnetic field greater than a stray magnetic field to magnetizable structural features of a microelectronic device that is part of a substrate wafer with other microelectronic devices, wherein the magnetizable structural features are separate from a magnetic sensor component of the microelectronic device, for a predetermined duration to align magnetic moments of the magnetizable structural features parallel to the magnetic field, wherein the magnetizable structural features comprise bond pads and wherein the magnetic sensor component includes a Hall plate; and

discontinuing application of the magnetic field after the predetermined duration.

11. A method, comprising:

applying a magnetic field greater than a stray magnetic field to magnetizable structural features of a microelectronic device, wherein the magnetizable structural features are separate from a magnetic sensor component of the microelectronic device, for a predetermined duration to align magnetic moments of the magnetizable structural features parallel to the magnetic field;

discontinuing application of the magnetic field after the predetermined duration;

applying a test magnetic field to a second microelectronic device comprising a magnetic sensor component and magnetizable structural features;

subsequently measuring a value of a parameter of the magnetic sensor component of the second microelectronic device; and

using the measured value of the parameter to estimate a desired orientation for the magnetic field applied to the second microelectronic device, prior to applying the magnetic field to the microelectronic device.

12. A method, comprising:

applying a magnetic field greater than a stray magnetic field to magnetizable structural features of a microelectronic device, wherein the magnetizable structural features are separate from a magnetic sensor component of the microelectronic device, for a predetermined duration to align magnetic moments of the magnetizable structural features parallel to the magnetic field;

discontinuing application of the magnetic field after the predetermined duration;

reading values of magnetic properties of the microelectronic device from a computer-readable memory;

estimating a value of a parameter of the magnetic sensor component as a function of a test orientation of the magnetic moments of the magnetizable structural features, using the values of the magnetic properties; and

estimating a desired orientation for the magnetic field applied to the microelectronic device, using the estimated value of the parameter, prior to applying the magnetic field to the microelectronic device.

13. A method, comprising:

applying a magnetic field greater than a stray magnetic field to magnetizable structural features disposed in a package housing an active circuit and a fluxgate magnetometer core, for a predetermined duration to align magnetic moments of the magnetizable structural features parallel to the magnetic field for a selected zero-field offset of the fluxgate magnetometer core; and

discontinuing application of the magnetic field after the predetermined duration.

14. The method of claim 13 , wherein the magnetic field is at least 10 mT.

15. The method of claim 13 , wherein the magnetizable structural features of the package comprise metal leads.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 9, 2016
From: GABRYS, ANN MARGARET; LEE, DOK WON
To: TEXAS INSTRUMENTS INCORPORATED
Reel/Frame 037929/0615 →
Continuity (1)
Related Publication 20170261564A1 · Sep 14, 2017