Single-chip magnetic field sensor bridge

Patent metadata

Field	Value
Publication number	US-9817084-B2
Application number	US-201414894258-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 28, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A single-chip magnetic field sensor bridge, comprising a substrate, a reference arm, a sensing arm, shielding structures, and wire bond pads is disclosed. The reference arm and the sense arm respectively comprise at least two rows/columns of reference element strings and sense element strings formed by electrically connecting one or more identical magnetoresistive sensing elements. The reference element strings and the sense element strings are alternately arranged. The magnetoresistive sensing elements are AMR, GMR or TMR sensing elements. The reference element strings are provided with shielding structures thereon, and the sensing element strings are located in gaps between two adjacent shielding structures. The shielding structures are arrays of elongated strips composed of permalloy or another soft ferromagnetic material. The sensors can be implemented as one of three different bridge structures, called a quasi-bridge, a half-bridge, or a full-bridge. This single-chip magnetic field sensor bridge has the advantages of small size, low cost, high sensitivity, small offset, good linearity, and good temperature stability.

First claim

The invention claimed is:

1. A single-chip magnetic field sensor bridge, comprising:
a substrate;
a half-bridge or a quasi-bridge on the substrate, the half-bridge or the quasi-bridge including:
a reference arm R 1 , which includes at least two row/column reference element strings, each reference element string includes one or more identical magnetoresistive sensor elements electrically interconnected;
a sensing arm S 1 , which includes at least two row/column sense element strings, each sense element string includes one or more identical magnetoresistive sensor elements electrically interconnected; the reference and the sensing arms have the same number of rows/columns, along the horizontal/vertical spacing directions, wherein the reference element strings of the reference arm R 1 are interleaved with the sense element strings of the sensing arm S 1 , and the spacing between the adjacent reference element strings and the adjacent sense element strings is the same;
at least three shielding structures, with a well-defined gap between the shielding structures, each reference element string has a corresponding shielding structure, each sense element string is located in the corresponding gap, and
further including multiple input and output wire bond pads,
wherein the magnetoresistive sensor elements include anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR) sensor elements.

2. The single-chip magnetic field sensor bridge according to claim 1 , wherein the magnetoresistive sensor elements include magnetic field sensor elements with a linear magnetic field response characteristic.

3. The single-chip magnetic field sensor bridge according to claim 1 , wherein the magnetoresistive sensor elements include magnetic field sensor elements with a multilayer magnetic field response characteristic.

4. The single-chip magnetic field sensor bridge according to claim 1 , wherein the reference element strings and the sense element strings have the same number of magnetoresistive sensing elements.

5. The single-chip magnetic field sensor bridge according to claim 1 , wherein the single-chip magnetic field sensor bridge includes three wire bond pads, the first of the three wire bond pads is used to supply the bias voltage, the second is used for the output signal, and the third is used for grounding, the reference arm R 1 , the sense arm S 1 all have their respective first end and second ends connected such that the first end of the reference arm R 1 is connected to the first wire bond pad, the third bond pad and the sense arm S 1 first end are electrically connected, the second bond pad is electrically connected with the second end of the reference arm R 1 as well as electrically connected with the second end of the sense arm S 1 .

6. The single-chip magnetic field sensor bridge according to claim 1 , wherein the single-chip magnetic field sensor bridge has three bond pads, the first bond pad is used for grounding, while the second and the third bond pads are used for the output, and the bridge includes two identical current sources (I 1 , I 2 ), both of the current sources (I 1 , I 2 ), the reference arm R 1 and the sense arm S 1 all respectively have a first end and a second end, the first wire bond pad is connected with the first end of the reference arm R 1 , the first end of the sensing arm S 1 , and additionally electrically connected with the first end of a current sources (I 1 , I 2 ), the second wire bond pad is electrically connected with the second end of reference arm R 1 and the second end of current source I 2 , the third wire bond pad is electrically connected with the second end of the sensing arm S 1 and the second end of current source I 1 .

7. The single-chip magnetic field sensor bridge according to claim 1 , wherein the shielding structures are elongated along the same horizontal/vertical direction, and they are composed of alloys including one or more of the materials Ni, Fe, Co, Si, B, Ni, Zr, or Al.

8. The single-chip magnetic field sensor bridge according to claim 1 , wherein there is a gap between the shielding structures chosen such that the magnetic field gain factor is between 1<A sns <100, and the magnetic field in the region above or below the magnetic shield structures is described by the magnetic field attenuation coefficient 0<A ref <1.

9. The single-chip magnetic field sensor bridge according to claim 1 , wherein the reference element string, the sense element string, and the bonds pads are electrically interconnected to each other.

10. The single-chip magnetic field sensor bridge according to claim 1 , wherein the substrate includes CMOS, and the CMOS, the reference arm, the sense arm, and the wire bond pads are lithographically defined on the substrate.

11. A single-chip magnetic field sensor bridge, comprising:
a substrate;
a full-bridge on the substrate, the full-bridge includes mutual interconnection between a first bridge arm and a second bridge arm, the first bridge arm includes a first reference arm R 1 , which includes at least two rows/columns of the first reference element strings, each first reference element string consists of one or more electrically interconnected magnetoresistive sensor elements; as well as a first sense arm S 1 , which includes at least two rows/columns of the first sense element strings, each first sense element string consists of one or more electrically interconnected magnetoresistive sensor elements;
the reference element strings and the sense element strings have the same number of rows/columns, and the spacing along the longitudinal/vertical direction, describing the adjacent first reference element strings and first sense element strings is defined by length L, wherein the reference element strings of the reference arm R 1 are interleaved with the sense element strings of the sensing arm S 1 ;
the second bridge arm includes a second reference arm R 2 , which includes at least two rows/columns of the first reference element strings, each reference element string consists of one or more electrically interconnected magnetoresistive sensor elements, as well as a second sense arm S 1 , which includes at least two rows/columns of the second sense element strings, each sense element string consists of one or more electrically interconnected magnetoresistive sensor elements;
the second reference element string and the second sense element string have the same number of rows/columns, and the spacing along the longitudinal/vertical direction, describing the adjacent second reference element strings and second sense element strings is defined by length L, wherein the reference element strings of the reference arm R 2 are interleaved with the sense element strings of the sensing arm S 2 ;
in the area between the first bridge arm and the second bridge arm the first reference element string and the second reference element string or the first sense element string and the second reference element string are located adjacent to each other;
the adjacent the first reference element string and the second reference element string or the first sense element string and the second reference element string are separated by a distance 2 L;
at least three shielding structures, wherein the shielding structures have a nearest neighbor spacing, and each of the first reference element strings and each of the second reference element strings are under a corresponding shielding structure, and each of the first sense element stings and each of the second elements strings is located in the gaps between the shielding structures; and
a multiplicity of input and output wire bond pads,
wherein the magnetoresistiv

Assignees

• Multidimension Technology Co Ltd

Inventors

• Deak James Geza

Classifications

• G01R17/105

  for measuring impedance or resistance · CPC title

• G01R33/09 Primary

  Magnetoresistive devices · CPC title