MAGNETIC SENSOR HAVING RESISTANCE ADJUSTING UNIT AND METHOD OF MANUFACTURING THE SAME

Abstract

A magnetic sensor capable of properly reducing a deviation of a central potential and a method of manufacturing the magnetic sensor are provided. A conductor is connected to an end of a fixed resistance element. The conductor includes a plurality of divisional path pieces and a common path piece. A current path length in a longitudinal direction of the conductor 35 is varied by cutting a part of the common path piece, thereby adjusting the resistance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

FIG. 1 is a partial schematic diagram illustrating a foldable cellular phone with a built-in magnetic sensor according to an embodiment (closed state).

FIG. 2 is a partial schematic diagram illustrating a foldable cellular phone with a built-in magnetic sensor according to the embodiment (opened state).

FIG. 3 is a partial top plan view illustrating a magnetic sensor according to the embodiment.

FIG. 4 is a partial and cross sectional view illustrating the magnetic sensor taken along a line 4-4 of FIG. 3.

FIG. 5A is a partial enlarged top plan view illustrating the magnetic sensor before cutting a conductor.

FIG. 5B is a partial enlarged top plan view illustrating the magnetic sensor after cutting the conductor.

FIG. 6 is a partial enlarged top plan view illustrating the magnetic sensor with a structure different from that shown in FIGS. 5A and 5B according to the embodiment.

FIG. 7 is a partial enlarged top plan view illustrating the magnetic sensor with a structure different from that shown in FIGS. 5A, 5B, and 6 according to the embodiment.

FIG. 8 is a partial enlarged cross-sectional view illustrating the magnetic sensor taken along Line 8-S shown in FIG. 7.

FIG. 9 is a partial enlarged top plan view illustrating the magnetic sensor with a structure different from that shown in FIGS. 5A, 5B, 6, and 7 according to the embodiment.

FIG. 10 is a diagram illustrating a circuit configuration of the magnetic sensor shown in FIG. 3.

FIG. 11 is a partial sectional view illustrating the magnetic sensor with a type different from that shown in FIG. 4.

FIG. 12 is a graph illustrating a hysteresis characteristic of a fixed resistance element, which prepares the magnetic sensor shown in FIG. 11.

FIG. 13 is a graph illustrating a relationship of a coupling magnetic field between a film thickness of a non-magnetic layer, a fixed layer of a magnetoresistance effect element, and a free layer.

FIG. 14 is a graph illustrating a relationship between an element width of the magnetoresistance effect element and a coercive force Hc of the free layer.

FIG. 15 is a graph illustrating the hysteresis characteristic of the magnetoresistance effect element shown in FIG. 4 and FIG. 11.

FIG. 16 is a process view illustrating a method of manufacturing the magnetic sensor according to an exemplary embodiment (partial top plan view).

FIG. 17 is a process diagram illustrating processes performed after the processes illustrated in FIG. 16 (partial top plan view).

FIG. 18 is a process diagram illustrating processes performed after the processes illustrated in FIG. 17 (partial top plan view).

FIG. 19 is a process diagram illustrating processes performed after the processes illustrated in FIG. 18 (partial top plan view).

Claims

1. A magnetic sensor comprising: at least one magnetoresistance element disposed on an element base;at least one fixed resistance element disposed on the element base; andterminal portions disposed on both sides in a longitudinal direction of the magnetoresistance element and on both sides in a longitudinal direction of the fixed resistance element,wherein a conductor is connected to at least one element of the magnetoresistance element and the fixed resistance element to adjust a resistance value between the terminal portions.

2. The magnetic sensor according to claim 1, wherein the conductor is connected to an end of a high-resistance element that is one of the magnetoresistance element and the fixed resistance element having a high resistance value and the conductor has a shape in which a current path length is shortened in the longitudinal direction.

3. The magnetic sensor according to claim 2, wherein the conductor includes at least three cuttable divisional path pieces, which are operable to come in contact with the high-resistance element, with gaps in the longitudinal direction therebetween, and a cuttable common path piece connecting the cuttable divisional path pieces to each other.

4. The magnetic sensor according to claim 3, wherein the gaps in the longitudinal direction between the divisional path pieces are different from each other.

5. The magnetic sensor according to claim 3, wherein the high-resistance element, which is one of the magnetoresistance element and the fixed resistance element having a high resistance value, has a shortened length in the longitudinal direction and the conductor is disposed in a removed part of the high-resistance element.

6. The magnetic sensor according to claim 1 wherein the magnetoresistance element and the fixed resistance element include an anti-ferromagnetic layer, a plurality of magnetic layers, a non-magnetic layer, and a protection layer serving as an uppermost layer, wherein the magnetoresistance element includes a fixed layer that includes at least one magnetic layer and of which magnetization direction is fixed and a free layer that includes the other magnetic layers and of which magnetization direction varies with an external magnetic field, the non-magnetic layer is interposed between the fixed layer and the free layer, and the anti-ferromagnetic layer is in contact with a surface opposite to the surface of the fixed layer where the non-magnetic is disposed; andwherein in the fixed resistance element, the at least one magnetic layer is in contact with the anti-ferromagnetic layer, and the magnetization directions of all the magnetic layers are fixed.

7. The magnetic sensor according to claim 1, wherein the magnetoresistance element and the fixed resistance element include an anti-ferromagnetic layer, a fixed layer, which is in contact with the anti-ferromagnetic layer and of which a magnetization direction is fixed, and a free layer that is opposed to the fixed layer with a non-magnetic layer therebetween and of which the magnetization directions vary with the external magnetic field, and wherein a first interlayer coupling magnetic field between the free layer and the fixed layer of the fixed resistance element is larger than a second interlayer coupling magnetic field between the free layer and the fixed layer of the magnetoresistance element.

8. A method of manufacturing a magnetic sensor, the method comprising the steps of: (a) forming a plurality of sets, each of which includes at least a magnetoresistance element and a fixed resistance, on a substrate and,(b) forming terminal portions on both sides in a longitudinal direction of the magnetoresistance element and on both sides in the longitudinal direction of the fixed resistance element,(c) connecting a conductor to a high-resistance element, which is one of the magnetoresistance element and the fixed resistance element having a high resistance value, to set a resistance value between the terminal portions connected to the high-resistance element within a range of a resistance value between the terminal portions connected to a low-resistance element.(d) cutting each set out of the substrate between the process (b) and the process (c), or after the process (c).

9. The method according to claim 8, wherein in the process (c), the conductor connected to the high-resistance element has a shape in which a current path length is shortened in the longitudinal direction by cutting.

10. The method according to claim 9, wherein the process (c) includes a first sub-process of setting the resistance value between the terminal portions connected to the high-resistance element to be lower than the resistance value between the terminal portions connected to the low-resistance element at the time of connecting the conductor, and a second sub-process of cutting a part of the conductor to shorten a current path length in the longitudinal direction of the conductor and increase the resistance value between the terminal portions connected to the high-resistance element, wherein the second sub-process is repeated until the resistance value between the terminal portions connected to the high-resistance element is within the range.

11. The method according to claim 10, wherein the conductor includes at least three cuttable divisional path pieces in contact with the high-resistance element with gaps therebetween in the longitudinal direction and a cuttable common path piece connecting the divisional path pieces, and the divisional path pieces or the common path piece is cut or the divisional path pieces and the common path piece are cut in the second sub-process of the (c) process.

12. The method according to claim 11, wherein the gaps in the longitudinal direction between the divisional path pieces have different lengths in the longitudinal direction, a cutting position of the divisional path piece or the common path piece is determined or cutting positions of the divisional path piece and the common path piece are determined in accordance with an increased amount of resistance value for the second sub-process of the process (c).

13. The method according to claim 8, wherein in the process (c), a part of the high-resistance element is removed to shorten a length in the longitudinal direction of the high-resistance element and the conductor is formed in the removed part to decrease a resistance value between the terminal portions connected to the high-resistance element lower than the resistance value before removing the part of the high-resistance element.