Thin-layer resistor device for use in an integrated circuit, integrated circuit with thin-layer resistor device

Abstract

Thin-film magnetoresistive sensor (10) for use in an integrated circuit, wherein the thin-film magnetoresistive sensor comprises the following: Thin-film magnetoresistive elements (100, 102, 104, 106, 108) formed in a first layer of the thin-film magnetoresistive sensor to form a circuit of the thin-film magnetoresistive sensor; a load compensation structure (60) comprising metallic load compensation elements (174A-174E) formed in a second layer of the thin-film magnetoresistance sensor (10), wherein the metallic load compensation elements (174A-174E) are arranged to compensate for a load applied to the thin-film magnetoresistance elements, and wherein the thin-film magnetoresistance elements (100, 102, 104, 106, 108) and the metallic load compensation elements are arc-shaped.

Description

BACKGROUNDTechnical field

[0001] The present disclosure relates to an improved thin film resistor device fabricated using microelectronic techniques and integrated circuits incorporating such a device. Description of the state of the art

[0002] Thin-film resistive sensors are used for a wide variety of applications. For example, magnetoresistive sensors can be used to determine an angular relationship between two parts of a system. Such sensors typically contain a number of resistive components. If these resistive components are well matched, they can help produce accurate measurements. When thin-film resistive devices are included on a single chip with other components, these other components can create uneven stress levels in the thin-film components. This can degrade the matching of the thin-film resistors. Furthermore, temperature changes in the sensor can affect parameters such as offset drift. This can also affect the accuracy of the device and can make calibration procedures expensive.

[0003] It would be advantageous to create a thin-film resistor device with improved component matching and more robust to temperature changes.

[0004] US 2006 / 0 228 879 A1 discloses a method for manufacturing an integrated thin-film resistor circuit. A first dielectric layer is formed over a substrate. A dummy fill layer is formed on the first dielectric layer, forming a structure for compensating for variations in a resistor head. A second dielectric layer is formed over the first dummy fill layer. A thin-film resistor is formed on the second dielectric layer. A first interlevel dielectric layer is formed on the first thin-film resistor and the second dielectric layer. A first metal layer is formed on the first interlevel dielectric layer, which electrically contacts a portion of the thin-film resistor. US 2014 / 0 118 017 A1 and US 6 818 966 B2 disclose further thin-film structures.

[0005] US 8,283,921 B2 discloses a magnetoresistive sensor for use in a position and orientation sensing system. The magnetoresistive sensor comprises an insulated substrate, a structure of metallic materials and / or semiconducting materials deposited on the surface of the insulating substrate, and a bias magnetic material deposited over the alternating structure of metallic material and semiconductor material.

[0006] US 2014 / 0 118 017 A1 relates to a multilayer wiring base plate comprising an insulating plate including a plurality of resin layers made of an insulating material, a wiring circuit provided in the insulating plate, a thin film resistor formed along at least one of the resin layers to be embedded in the resin layer and inserted into the wiring circuit, and a thermal expansion and contraction restricting layer formed to be embedded in the resin layer adjacent to the resin layer in which the thin film resistor is formed to be embedded therein, and arranged along the thin film resistor and having a smaller linear expansion coefficient than a linear expansion coefficient of the adjacent resin layers.

[0007] US 6,818,966 B2 relates to a method and structure for controlling the surface properties in the dielectric layers in a thin-film component, which are provided to improve the trimming process of a thin-film element. A metal fill is configured with a uniform fill pattern beneath an array of thin-film resistors and may include a plurality of smaller features or peaks that result in a finer fill pattern that improves control of the topology of the dielectric layers. The fill pattern can be configured in various ways, e.g., as a fill pattern parallel to the thin-film resistor, as a fill pattern perpendicular to the thin-film resistor, or as a fill pattern with a checkerboard configuration.The method and apparatus for controlling the dielectric layers may also provide for a reduction in the disturbances that may be caused by the back reflection of the focused energy by including a dispersion arrangement configured to provide a dispersive gradation of the laser energy below the thin film resistance, thus reducing the interaction of the reflected energy with the incident laser beam.

[0008] US 6,252,390 B1 relates to a current-determining device having an output at which representations of input currents are provided, comprising an input conductor for the input current and a current sensor supported on a substrate that is electrically isolated from each other, but the sensor is positioned in the magnetic fields generated around the input conductor due to any input currents. The sensor extends along the substrate in a direction substantially perpendicular to the extension of the input conductor and consists of at least one pair of ferromagnetic thin-film layers separated by a non-magnetic conductive layer.The sensor may be electrically connected to an electronic circuit formed in the substrate which includes a non-linearity adaptation circuit to provide representations of the input currents with increased accuracy despite the non-linearities in the current sensor, and may include further current sensors in bridge circuits.

[0009] US 2008 / 0 116 535 A1 relates to a shielding structure for shielding a region of a semiconductor device (e.g., a magnetoresistive random access memory or “MRAM”) that is susceptible to electromagnetic fields, comprising a stress relief layer (e.g., electroplated Ni) formed over the semiconductor device in a shielding region that substantially corresponds to the region susceptible to electromagnetic fields, and a magnetic shielding layer (e.g., an electroplated permalloy or mu-metal layer) that is mechanically coupled to the stress relief layer within the shielding region, wherein the magnetic shielding layer has a stress state that is substantially opposite to that of the stress relief layer.

[0010] US 2013 / 0 168 808 A1 relates to a MEMS power inductor and in particular to a MEMS power inductor with magnetic laminations formed in a crack-resistant, high aspect ratio structure.

[0011] US 2014 / 0 353 785 A1 relates to an integrated AMR (Anisotropic Magnetoresistance) type magnetoresistive sensor consisting of a magnetoresistive strip made of ferromagnetic material and having an elongated shape with a preferred magnetization direction (EA). A set / reset coil has a portion extending across and transverse to the magnetoresistive strip. A concentration region, also made of ferromagnetic material, extends across the length of the set / reset coil to form a magnetic circuit for the field generated by the set / reset coil during the steps of refreshing and maintaining the magnetization of the magnetoresistive coil. Summary of certain aspects of the invention

[0012] Thin-film resistive sensors typically contain a number of resistive components. These components should be well-matched for the sensor to provide accurate readings. When a sensor is integrated into an integrated circuit, the resistive components may be formed above or below metallic traces that form part of the other components. As a result, the thin-film resistive components are subjected to various levels of stress. This disclosure provides a structure designed to mitigate the effects of stress.

[0013] According to a first aspect of the present invention, there is provided a thin-film magnetoresistive device for use in an integrated circuit according to claim 1, comprising: a plurality of thin-film resistive elements formed in a first layer of the thin-film resistive device; and a load balancing structure comprising a plurality of load balancing elements formed in a second layer of the thin-film resistive device, the load balancing elements being arranged to balance the load imposed on the resistive components.

[0014] Another aspect of this disclosure is a monolithic integrated circuit with load balancing according to claim 11. The monolithic integrated circuit comprises thin-film resistive elements arranged in a first layer of the monolithic integrated circuit as a sensor. The monolithic integrated circuit also comprises metallic elements in a second layer of the monolithic integrated circuit, wherein the second layer is adjacent to the first layer. The metallic elements are arranged in positions of the second layer that correspond to positions of the respective thin-film resistive elements in the first layer.

[0015] Another aspect of this disclosure is a thin film magnetoresistive device according to claim 15, comprising a plurality of thin film resistive elements arranged as a sensor and means for reducing a difference in stress applied to the different thin film resistive elements of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of this disclosure will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1 is a circuit diagram showing a thin film magnetoresistive sensor; Fig. 2 is a diagram showing the output of the sensor of Fig. 1 shows; Fig. 3 is a plan view of an integrated circuit that incorporates the sensor of Fig. 1 according to an embodiment of the disclosure; Fig. 4 is a top view of an integrated circuit including a thin film magnetoresistive sensor according to an embodiment of the disclosure; Fig. 5 a plan view of a section of the circuit of Fig. 4 is; Fig. 6 a plan view of another section of the circuit of Fig. 4 is; Fig. 7 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 4 is; Fig. 8 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 9 is an enlarged plan view of a section of the circuit of Fig. 8 is; Fig. 10 is an enlarged plan view of another section of the circuit of Fig. 8 is; Fig. 11 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 8 is; Fig. 12 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 13 is an enlarged plan view of a section of the circuit of Fig. 12 is; Fig. 14 is an enlarged plan view of another section of the circuit of Fig. 12 is; Fig. 15 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 12 is; Fig. 16 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 17 is an enlarged plan view of a section of the circuit of Fig. 16 is; Fig. 18 is an enlarged plan view of another section of the circuit of Fig. 16 is; Fig. 19 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 16 is; Fig. 20 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 21 is an enlarged plan view of a section of the circuit of Fig. 20 is; Fig. 22 is an enlarged plan view of a further section of the circuit of Fig. 20 is; Fig. 23 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 20 is; Fig. 24 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 25 is an enlarged plan view of a section of the circuit of Fig. 24 is; Fig. 26 is an enlarged plan view of a further section of the circuit of Fig. 24 is; Fig. 27 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 24 is; Fig. 28 is a plan view of an integrated circuit including a thin film magnetoresistive sensor according to another embodiment of the disclosure; Fig. 29 is an enlarged plan view of a section of the circuit of Fig. 28 is; Fig. 30 is an enlarged plan view of another section of the circuit of Fig. 28 is; and Fig. 31 is an enlarged plan view of a group of thin-film resistor elements of the circuit of Fig. 28 is. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0017] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein may be implemented in a variety of ways, for example, as defined and covered by the claims. Reference is made throughout this description to the drawings, in which like reference numerals may designate identical or functionally similar elements. It is understood that elements shown in the figures are not necessarily drawn to scale. Furthermore, it is understood that certain embodiments may include more elements than shown in any one drawing and / or a subset of the elements shown in a drawing. Further, some embodiments may include any suitable combination of features from two or more drawings.

[0018] The present disclosure provides a thin-film resistive device that may be a magnetoresistive sensor and that includes a stress-compensating layer to mitigate the effects of underlying (or overlying) metal in the integrated circuit. The thin-film devices discussed herein may be used in a variety of magnetoresistive sensors, such as anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, or tunneling magnetoresistive (TMR) sensors. Typically, the thin-film resistive device is formed over other components. These other components may include metallic traces that, once integrated, may impose a stress on the resistive elements of the thin-film device. This stress may alter the characteristic impedance of the resistive elements.In a sensor with a bridge circuit, this can result in the resistors being mismatched. The stress-compensation layer has a periodic pattern of metallic conductors underlying the device. This can cause the device's resistive elements to "see" the same underlying metal, negating the influence of other metal traces found beneath the device.

[0019] Fig. 1 shows a circuit diagram of a thin-film magnetoresistive sensor (TF magnetoresistive sensor) 10. The sensor 10 of Fig. 1 is an AMR sensor. The sensor 10 contains two Wheatstone bridges connected in parallel. A first Wheatstone bridge comprises TF magnetoresistors 12, 14, 16, and 18. A second Wheatstone bridge comprises TF magnetoresistors 20, 22, 24, and 26. The resistors of each bridge are connected in a conventional bridge configuration. Both bridges share a connection to ground (GND) and a connection to a positive voltage (Vcc). Sensor 10 contains four output lines. These output lines are labeled +V according to the corresponding voltages assigned to these output lines. 01 , +V 02 , - V 01 and - V 02 The first Wheatstone bridge is connected to the output lines +V 01 and -V 01 The second Wheatstone bridge is connected to the output lines +V 02 and -V 02 coupled.

[0020] Since these bridges are used as sensors, their relative orientation is significant. Accordingly, in the first Wheatstone bridge, resistors 12 and 16 are parallel to each other, but orthogonal to resistors 14 and 18. Similarly, resistors 20 and 26 in the second Wheatstone bridge are parallel to each other, but orthogonal to resistors 22 and 24. Furthermore, the first Wheatstone bridge is oriented at a 45° angle to the second Wheatstone bridge. Accordingly, resistor 14 is at a 45° angle to resistor 22, resistor 16 is at a 45° angle to resistor 24, resistor 18 is at a 45° angle to resistor 26, and resistor 12 is at a 45° angle to resistor 20. In Fig. 1, a is the direction of a magnetic field applied to the sensor 10.

[0021] Fig. Figure 2 is a graph showing the output of sensor 10 in relation to a varying magnetic field. The graph shows the magnetic field angle α (degrees) on the x-axis and the output voltage (mV) on the y-axis. The graph shows the output voltages V 01 and V 02 , where: V01=+V01−−V01 V02=+V02−−V02

[0022] As from Fig. 2 can be seen, V oi and V o2 both sinusoidal with respect to the varying magnetic field angle.

[0023] Fig. Figure 3 shows a physical configuration of the TF magnetoresistive sensor 10 according to one embodiment of the disclosure. In this embodiment, the stress compensation layer is removed so that the other components of the sensor can be clearly shown and described. Each resistor in the sensor 10 is formed from multiple groups of thin-film magnetoresistive elements. In certain embodiments, the thin-film resistive elements may have a thickness in the range of approximately 20 Â to 5000 Â. In the example of Fig. 3, each resistor contains six groups of TF elements, and each group contains five thin-film resistance elements. The resistance elements shown are arc-shaped and parallel to the other elements of the same group. The resistance elements shown are of equal length and are interconnected by thin-film interconnect elements at alternating ends to connect the elements in a series circuit. The sensor 10 also contains six bonding pads. One bonding pad 30 is used for connection to V CC . A bonding island 32 is used to connect to the output line +V 02 A bonding pad 34 is used to connect to the output line +V 01 A bonding pad 36 is used for connection to GND. A bonding pad 38 is used for connection to the output line - V 01 . A bonding island 32 is used for connection to the output line -V 02 .

[0024] Resistor 12 contains groups of elements 12A to 12F. Each group is connected to the next group by a thin-film interconnect element. Group 12A is coupled to GND via an interconnect element 42. Group 12F is connected to -V 01 coupled by an intermediate connecting element 44. Groups 12A to 12F are oriented such that the relative orientation of the groups of elements is 45° to the x-axis. The arcs of the elements of groups 12B, 12D, and 12F are oriented at an angle of 180° to the arcs of the elements of groups 12A, 12C, and 12E. Each group of elements is offset from an adjacent group such that lines intersecting the centers of the elements of each group are spaced apart by a distance approximately equal to the length of an element.

[0025] Resistor 14 contains groups of elements 14A to 14F. Each group is connected to the next group by a thin-film interconnect element. Group 14A is labeled V cc connected via an intermediate connecting element 46. The group 14F is connected to -V oiconnected by an intermediate connecting element 44. The groups 14A to 14F are oriented such that the relative orientation of the groups of elements is 45° to the x-axis. The arcs of the elements of groups 14B, 14D, and 14F are oriented at an angle of 180° to the arcs of the elements of groups 14A, 14C, and 14E. Each group of elements is offset from an adjacent group such that lines intersecting the centers of the elements of each group are spaced apart by a distance approximately equal to the length of one element. Furthermore, the groups 14A to 14F are aligned at 90° to the respective groups 12A to 12F, thereby maintaining the relative orientation between the resistors 12 and 14 arranged in Fig. 1. In addition, resistors 12 and 14 are interconnected by intermediate connector 44.

[0026] Resistor 16 contains groups of elements 16A to 16F. Each group is connected to the next group by a thin-film interconnect element. Group 16A is labeled V cc via the intermediate connection element 46. The group 16F is connected to +V via an intermediate connection element 48 01coupled. Groups 16A to 16F are oriented such that the relative orientation of the groups of elements is 45° to the x-axis. The arcs of the elements of groups 16B, 16D, and 16F are oriented at an angle of 180° to the arcs of the elements of groups 16A, 16C, and 16E. Each group of elements is offset from an adjacent group such that lines intersecting the centers of the elements of each group are spaced apart by a distance approximately equal to the length of one element. Furthermore, groups 16A to 16F have the same orientation as each of groups 12A to 12F, thereby achieving the same relative orientation between resistors 12 and 16 shown in Fig. 1 is shown.

[0027] Resistor 18 contains groups of elements 18A to 18F. Each group is connected to the next group by a thin-film interconnect element. Group 18A is coupled to GND via interconnect element 42. Group 18F is coupled to +V via interconnect element 48. 01coupled. The groups 18A to 18F are oriented such that the relative orientation of the groups of elements is 45° to the x-axis. The arcs of the elements of groups 18B, 18D, and 18F are oriented at an angle of 180° to the arcs of the elements of groups 18A, 18C, and 18E. Each group of elements is offset from an adjacent group such that lines intersecting the centers of the elements of each group are spaced apart by a distance approximately equal to the length of one element. Furthermore, the groups 18A to 18F are oriented at an angle of 90° to the respective groups 16A to 16F, thereby determining the relative orientation between the resistors 16 and 18 arranged in Fig. 1. Additionally, resistors 16 and 18 are coupled together by interconnection element 48. Accordingly, resistors 12, 14, 16, and 18 are coupled together and oriented to form a first Wheatstone bridge.

[0028] Resistor 20 contains groups of elements 20A to 20F. Each group is connected to the next group by a thin-film interconnect element. Group 20A is coupled to GND via interconnect element 42. Group 20F is connected to -V 02connected by the intermediate connecting element 50. Groups 20A to 20F are oriented such that the relative orientation of the groups of elements is 90° to the x-axis. The arcs of the elements of groups 20B, 20D, and 20F are oriented at an angle of 180° to the arcs of the elements of groups 20A, 20C, and 20E. Each group of elements is aligned with an adjacent group such that lines intersecting the centers of the elements of each group coincide.

[0029] Resistor 22 contains groups of elements 22A to 22F. Each group is connected to the next group by a thin-film interconnect element. Group 22A is labeled V cc connected via the intermediate connecting element 46. The group 22F is connected to - V 02connected by the intermediate connecting element 50. The groups 22A to 22F are oriented such that the groups of elements are parallel to the x-axis. The arcs of the elements of groups 22B, 22D, and 22F are oriented at an angle of 180° to the arcs of the elements of groups 22A, 22C, and 22E. Each group of elements is offset from an adjacent group such that lines intersecting the centers of the elements of each group are spaced apart by a distance greater than the length of an element. Furthermore, the groups 22A to 22F are aligned at an angle of 90° to the respective groups 20A to 20F, thereby determining the relative orientation between the resistors 20 and 22 arranged in Fig. 1. In addition, the resistors 20 and 22 are interconnected by the interconnect element 50.

[0030] Resistor 24 contains groups of elements 24A to 24F. Each group is connected to the next group by a thin-film interconnect element. Group 24A is labeled V CC coupled via the intermediate connection element 46. The group 24F is connected via the intermediate connection element 52 to +V 02 coupled. Groups 24A to 24F are oriented such that the relative orientation of the groups of elements is 90° to the x-axis. The arcs of the elements of groups 24B, 24D, and 24F are oriented at an angle of 180° to the arcs of the elements of groups 24A, 24C, and 24E. Each group of elements is aligned with an adjacent group such that lines intersecting the centers of the elements of each group coincide. Furthermore, groups 24A to 24F have the same orientation as each of groups 20A to 20F, thereby achieving the same relative orientation between resistors 20 and 24, which in Fig. 1 is shown.

[0031] Resistor 26 contains groups of elements 26A to 26F. Each group is connected to the next group by a thin-film interconnect element. Group 26A is coupled to GND via interconnect element 42. Group 26F is coupled to +V via interconnect element 52. 02connected. The groups 26A to 26F are parallel to the x-axis. The arcs of the elements of groups 26B, 26D, and 26F are oriented at an angle of 180° to the arcs of the elements of groups 26A, 26C, and 26E. Each group of elements is offset from an adjacent group so that lines intersecting the centers of the elements of each group are spaced apart by a distance greater than the length of an element. Furthermore, the groups 26A to 26F are oriented at an angle of 90° to the respective groups 24A to 24F, thereby achieving the relative orientation between the resistors 24 and 26, which in Fig. 1. In addition, resistors 24 and 26 are interconnected by the interconnecting element 52. Accordingly, resistors 20, 22, 24, and 26 are coupled together and oriented to form a first Wheatstone bridge. Furthermore, resistors 20 to 26 are connected in the same manner as in Fig. 1 shown oriented at an angle of 45° to the resistors 12 to 18.

[0032] It may be desirable for the resistors and their respective resistive elements to be well matched. Underlying and overlying metal traces disposed on the same chip can influence the amount of stress the thin-film elements are subjected to. Accordingly, if resistor 12 is deposited over a metal trace and resistor 14 is deposited over a smooth intermetallic dielectric, these elements may not be as well matched as desired.

[0033] Fig. 4 shows a TF magnetoresistive sensor 10 according to an embodiment of this disclosure. In this embodiment, the sensor 10 includes a stress compensation layer 60. This is indicated by the generally darker areas corresponding to the position of the groups of TF elements. The stress compensation layer 60 includes a metallic layer formed beneath the TF elements in the chip. An insulating layer is formed between the TF elements and the metallic layer. In this example, the metallic layer is formed as a series of linear metallic conductors. The conductors are arranged in groups, with each group corresponding to a group of TF elements. The stress compensation layer 60 includes metallic conductor groups 62A to 62F, 64A to 64F, 66A to 66F, 68A to 68F, 70A to 70F, 72A to 72F, 74A to 74F, and 76A to 76F.

[0034] The shape formed by a group of conductors is essentially the same as the shape formed by each group of TF elements. However, as will be seen below, the conductor groups may cover an area slightly larger than the corresponding group of TF elements. Furthermore, some of the groups of conductors may overlap and share the same linear metallic conductors, as described below, for example. Fig. 4, two areas 78 and 80 are outlined by dashed lines. These areas are in Fig. 5 and Fig. 6 is shown in more detail.

[0035] Fig. 5 shows a close-up view of area 78 from Fig. 4. Fig. Figure 5 shows groups of TF elements 16F, 16E, 16D, 18F, and 18E. These groups are connected to the bond pad 34 via the TF interconnect 48. The groups are interconnected via TF interconnects 82, 84, and 86. Each group of TF elements has a corresponding group of metallic conductors in the stress compensation layer. In this example, groups of metallic conductors 66F, 66E, 66D, 68F, and 68E are shown. Further details of the metallic conductors are described below. In this example, groups 66F and 66E are separate. However, due to the proximity of the groups of elements 18F and 18E, groups of conductors 68F and 68E share seven linear metallic elements.

[0036] Fig. 6 shows a close-up view of area 80 from Fig. 4. Fig. Figure 6 shows groups of TF elements 26F, 26E, 24F, and 24E. These groups of elements are connected to the bond pad 32 via the interconnect element 52. The groups are interconnected via interconnect elements 88 and 90. Each group of elements has a corresponding group of metallic conductors in the stress compensation layer. In this example, four complete groups of metallic conductors 76F, 76E, 74F, and 74E are shown. In this example, the groups 76F, 76E, 74F, and 74E are separated.

[0037] Fig. Figure 7 shows the details of the group of TF elements 26F used in Fig. 6. The group comprises five magnetoresistive elements 100, 102, 104, 106, and 108. Each element has a generally arcuate shape, although in fact each element shown has a number of short linear sections. In this example, each element contains four linear sections. The elements may, for example, be about 60 µm long and 4 µm wide. The elements are adjacent to one another and arranged in parallel. A gap of about 4 µm may be formed between the elements. A first end of the element 100 is connected to a thin-film interconnect element 52. As shown in Fig. 4, this interconnect element couples the element group 26F to the bond pad 32. A second end of the element 100 is connected to a thin-film interconnect element 110, which is connected to a second end of the element 102. A first end of the element 102 is connected to a thin-film interconnect element 112, which is connected to a first end of the element 104. A second end of the element 104 is connected to a thin-film interconnect element 114, which is connected to a first end of the element 106. The first end of the element 106 is connected to a thin-film interconnect element 116, which is connected to a first end of the element 108. A second end of the element 108 is connected to the thin-film interconnect element 88. As shown in Fig. As shown in Figure 4, this interconnect element couples group 26F to group 26E. The arrangement described above results in a meandering resistive element path. The group of resistive elements together forms a shape corresponding to a rectangle with two opposing curved edges and two opposing straight edges.

[0038] Fig. 7 also shows a part of the load compensation layer 60. In particular, Fig. 7 the group of conductors 76F. The group 76F comprises several linear metallic conductors. In this example, there are 30 conductors. Given the relatively large number of conductors, they are not individually numbered. The conductors can each be approximately 45 µm long and 1 µm wide. They are arranged in parallel and can be approximately 1 µm apart. They are oriented in a direction perpendicular to an imaginary line arranged between the first and second ends of the resistive elements. In itself, the angle at which the metallic conductors intersect the resistive elements varies depending on where the intersection point occurs. In Fig. 7, each of the metallic conductors extends beyond the edges of the outer elements 100 and 108 by a distance similar to the width of the elements. Similarly, the metallic conductors at both ends of the elements may extend beyond the ends of the elements, for example, by a distance of approximately 4 µm. The metallic conductors therefore define a stress compensation area similar in shape to the area defined by the elements. The stress compensation area in Fig. However, 7 is larger because it extends beyond the elements as described above. Furthermore, the metallic elements may all have a narrower width than the TF elements. In one example, the metallic elements may have between one-fifth and one-tenth the width of the resistive elements. The spacing between the metallic elements may be similar to their widths. In one example, for TF elements that are 4 µm wide, the metallic elements may have widths of 0.4 µm and a separation of 0.4 µm.

[0039] As a result of this arrangement, each resistive element can see virtually the same amount of underlying metal as the other resistive elements. Therefore, stresses caused by other underlying metal traces can be substantially or even completely equalized across the resistive elements.

[0040] Fig. Figure 8 shows the TF magnetoresistive sensor 10 in another embodiment of this disclosure. In this embodiment, the sensor 10 includes the same components as in the previous embodiments. However, the stress compensation layer 60 takes a different shape. In this embodiment, the metallic layer is formed as a series of linear metallic conductors. However, the conductors do not run continuously beneath the elements of each group of elements. Instead, they extend only beneath the respective element, as described below. The conductors are arranged in groups, with each group corresponding to a group of TF elements. The stress compensation layer 60 includes metallic conductor groups 122A to 122F, 124A to 124F, 126A to 126F, 128A to 128F, 130A to 130F, 132A to 132F, 134A to 134F, and 136A to 136F. Fig. 8, two areas 140 and 142 are outlined by dashed lines. These areas are in Fig. 9 and 10 respectively.

[0041] Fig. 9 shows a close-up view of area 140 from Fig. 8. Fig. Figure 9 shows groups of elements 16F, 16E, 16D, 18F, and 18E. These groups are connected to the bond pad 34 via a TF interconnect 48. The groups are interconnected via TF interconnects 82, 84, and 86. Each group of elements has a corresponding group of metallic conductors in the stress compensation layer 60. In this example, the groups of metallic conductors 126F, 126E, 126D, 128F, and 126E are shown. Further details of the metallic conductors are described below.

[0042] Fig. 10 shows a close-up view of area 142 from Fig. 8. Fig. Figure 10 shows groups of elements 26F, 26E, 24F, and 24E. These elements are connected to bond pad 32 via an interconnect element 52. The groups are coupled to each other via interconnect elements 88 and 90. Each group of elements has a corresponding group of metallic conductors. In this example, four complete groups of metallic conductors 136F, 136E, 134F, and 134E are shown.

[0043] Fig. Figure 11 shows the details of the group of elements 26F used in Fig. 10. The same reference numerals are used for components that are Fig. 7 are common. Fig. 11 also shows part of the load compensation layer 60. Fig. Figure 11 shows the group of conductors 136F. Group 136F comprises five subgroups of linear metallic conductors. In this example, there are subgroups 144A, 144B, 144C, 144D, and 144E. Each subgroup has thirty conductors. Given the relatively large number of conductors, they are not individually numbered. The conductors can have the same width and spacing as those in Fig. 7. They are oriented in a direction perpendicular to an imaginary line passing between the first and second ends of the resistance elements in Fig. 11 is drawn. In itself, the angle at which the metallic conductors intersect the resistive elements varies depending on where the intersection occurs. In this example, each linear conductor extends under only one resistive element. Each of the metallic conductors extends beyond the edges of its respective elements by an amount that may be substantially less than the width of the elements. Similarly, the metallic conductors at each end of the elements extend beyond the ends of the elements. The metallic conductors therefore define a load balancing area similar in shape to the area defined by each element. However, in Fig. 11, the load balancing area is larger because it extends beyond the elements as described above. Furthermore, the illustrated metallic elements have a smaller width than the TF elements. In one example, the metallic elements may have between one-fifth and one-tenth the width of the resistive elements. The spacing between the metallic elements may be similar to their widths. In one example, for TF elements that are 4 µm wide, the metallic elements may have widths of 0.4 µm and a separation of 0.4 µm.

[0044] Fig. Figure 12 shows the TF magnetoresistive sensor 10 in another embodiment of this disclosure. In this embodiment, the sensor 10 includes the same components as in the previous embodiments. However, the stress compensation layer 60 takes a different shape. In this embodiment, the metallic layer is formed as a series of arcuate metallic conductors. There are five metallic elements, each corresponding to a TF resistive element. Each metallic element has substantially the same shape as the corresponding resistive elements, as described in more detail below. The conductors are arranged in groups, with each group corresponding to a group of TF elements. The stress compensation layer 60 contains metallic conductor groups 152A to 152F, 154A to 154F, 156A to 156F, 158A to 158F, 160A to 160F, 162A to 162F, 164A to 164F and 166A to 166F. In Fig. 12, two areas 170 and 172 are outlined by dashed lines. These areas are in Fig. 13 and Fig. 14 is shown in more detail.

[0045] Fig. 13 shows a close-up view of area 170 from Fig. 12. Fig. Figure 13 shows groups of elements 16F, 16E, 16D, 18F, and 18E. These groups are connected to the bond pad 34 via a TF interconnect 48. The groups are coupled to each other via TF interconnects 82, 84, and 86. Each group of elements has a corresponding group of metallic conductors in the stress compensation layer 60. In this example, groups of metallic conductors 156F, 156E, 156D, 158F, and 156E are shown. Further details of the metallic conductors are described below.

[0046] Fig. 14 shows a close-up view of area 172 from Fig. 12. Fig. Figure 14 shows groups of elements 26F, 26E, 24F, and 24E. These elements are connected to bond pad 32 via an interconnect element 52. The groups are coupled to each other via interconnect elements 88 and 90. Each group of elements has a corresponding group of metallic conductors. In this example, four complete groups of metallic conductors 166F, 166E, 164F, and 164E are shown.

[0047] Fig. Figure 15 shows the details of the group of elements 26F used in Fig. 14. The group comprises five magnetoresistive elements 100, 102, 104, 106, and 108. Fig. 15 also shows part of the load compensation layer 60. Fig. Figure 15 shows the group of conductors 166F. The group 166F includes five metallic elements 174A, 174B, 174C, 174D, and 174E. The metallic elements, in one example, are each approximately 60 µm long and 6 µm wide. They are arranged in parallel and may be approximately 2 µm apart. Each element is generally arc-shaped. However, like the resistive elements, they are actually formed from four short linear sections, as shown. The metallic elements have substantially the same shape as the resistive elements. However, the metallic elements shown are slightly larger than the resistive elements, so the metallic elements extend beyond the edges of the resistive elements. In this example, the metallic elements extend beyond the edges of the resistive elements by 1 µm, which is significantly less than the width of the elements. The metallic elements may be approximately 50% larger than the resistive elements.The metallic conductors therefore define a load-balancing area similar in shape to the area defined by each element. However, the load-balancing area shown is larger because it extends beyond the elements, as described above.

[0048] Fig. Figure 16 shows the TF magnetoresistive sensor 10 according to another embodiment of this disclosure. The sensor 10 includes the same components as in Fig. 12. However, the load compensation layer 60 differs from that shown in Fig. 12. The metallic layer is formed as a series of parallel elongated metallic elements. Instead of being limited to the area immediately beneath each TF element or group of elements, the metallic layer 60 extends from Fig. 16 into the area between and around each group of TF elements. In this example, the metallic elements together form a rectangular shape 180 that is large enough to extend under all groups of TF elements of the TF sensor 10. In Fig. 17 and Fig. 18 are the same areas as those shown by the dashed lines 170 and 172 in Fig. 12 are shown in more detail.

[0049] Fig. Figure 17 shows groups of elements 16F, 16E, 16D, 18F, and 18E. These groups are connected to the bond pad 34 via a TF interconnect element 48. The groups are coupled to each other via TF interconnect elements 82, 84, and 86. Fig. Figure 18 shows groups of elements 26F, 26E, 24F, and 24E. These elements are connected to the bond pad 32 via an intermediate connection element 52. The groups are coupled to each other via intermediate connection elements 88 and 90.

[0050] Fig. Figure 19 shows the details of the group of elements 26F, which in Fig. 18 is shown. Fig. Figure 19 also shows the conductors 180 of the load balancing structure 60. The metallic conductors may each be approximately 1 µm wide. They are arranged in parallel and may be approximately 1 µm apart. The metallic conductors therefore define a load balancing region that extends beneath all of the illustrated resistive elements.

[0051] Fig. Figures 20 through 23 show another example of a stress equalization layer 60 in which the conductors 182 are arranged as a grid beneath all of the TF resistor elements. As shown, the grid includes a first set of substantially parallel conductors and a second set of substantially parallel conductors, with the conductors of the first set being substantially orthogonal to the conductors of the second set.

[0052] Fig. 24 to 27 show another example of a stress equalization layer 60 in which the conductors 184 are arranged as a series of circles, the circles being formed in rows and columns extending under all of the resistive TF elements.

[0053] Fig. Figure 28 shows a TF magnetoresistive sensor 10 in which the stress compensation layer 60 can also function as a heating element. The stress compensation layer 60 is the stress compensation layer used in Fig. 4 to 7, however, there are certain differences. As described in more detail below, the elements of the stress compensation layer 60 are coupled to one another and are also coupled to interconnecting elements that complete an electrical circuit. Therefore, current can be conducted through the stress compensation layer, thereby heating the structure. The structure 60 includes a metallic layer formed as a series of linear metallic conductors, in a manner similar to that shown in Fig. 4 to 7. Layer 60 includes groups of metallic conductors 192A to 192F, 194A to 194F, 196A to 196F, 198A to 198F, 200A to 200F, 202A to 202F, 204A to 204F, and 206A to 206F. Fig. 28, two areas 208 and 210 are outlined by dashed lines. These areas are in Fig. 29 and Fig. 30. The metallic conductors are coupled together by various metallic interconnecting elements, including, for example, interconnecting elements 212, 214, 216, 218, 220, and 222. The interconnecting elements also couple the metallic conductors to interconnecting elements 224 and 226 so that the metallic conductors can be coupled to a power source.

[0054] Fig. 29 shows a close-up view of area 208 of Fig. 28. Fig. Figure 29 shows groups of elements 16F, 16E, 16D, 18F, and 18E. These groups are connected to bond pad 34 via a TF interconnect 48. The groups are coupled together via TF interconnects 82, 84, and 86. Each group of elements has a corresponding group of metallic conductors in the stress compensation layer. In this example, groups of metallic conductors 196F, 196E, 196D, 198F, and 198E are shown. Also shown are various metallic interconnects. Groups of conductors 198F and 196F are coupled together by an interconnect 216. Groups of conductors 196F and 196E are coupled together by an interconnect 230. Groups of conductors 196E and 196D are coupled together by an intermediate connection element 232. Groups of conductors 198F and 198E are coupled together by an intermediate connection element 234.Further details of the metallic conductors are described below.

[0055] Fig. 30 shows a close-up view of area 210 from Fig. 28. Fig. Figure 30 shows groups of elements 26F, 26E, 24F, and 24E. These groups of elements are connected to the bond pad 32 via the interconnect element 52. The groups are coupled together via interconnect elements 88 and 90. Each group of elements has a corresponding group of metallic conductors in the stress compensation layer. In this example, four complete groups of metallic conductors 206F, 206E, 204F, and 204E are shown. Also shown are various metallic interconnect elements. Groups of conductors 206F and 204F are coupled together by an interconnect element 218. Groups of conductors 206F and 206E are coupled together by an interconnect element 238. Groups of conductors 204F and 204E are coupled together by an interconnect element 242.

[0056] Fig. Figure 31 shows a closer view of the group of elements 26F, which in Fig. 30. The Fig. 31 is similar to the arrangement shown in Fig. 7 and corresponding reference numerals have been used. Fig. 31 also shows a part of the load compensation layer 60. In particular, Fig. 31 the group of conductors 206F. The group 206F comprises several linear metallic conductors. In this example, there are thirty conductors. Given the relatively large number of conductors, they are not individually numbered. The conductors can each be approximately 45 µm long and 1 µm wide. They are arranged in parallel and can be approximately 1 µm apart. They are oriented in a direction perpendicular to an imaginary line extending between the first and second ends of the resistive elements in Fig. 31. In itself, the angle at which the metallic conductors intersect the resistance elements varies depending on where the intersection point occurs. Each of the metallic conductors extends beyond the edges of the outer elements 100 and 108 by a distance similar to the width of the elements. Similarly, the metallic conductors at both ends of the elements extend beyond the ends of the elements in Fig. 31, for example, by a distance of approximately 2 µm. The metallic conductors therefore define a load balancing area similar in shape to the area defined by the elements. However, the illustrated load balancing area is larger because it extends beyond the elements as described above. Furthermore, the metallic elements all have a smaller width than the TF elements. In one example, the metallic elements may have between one-fifth and one-tenth the width of the resistive elements. The spacing between the metallic elements may be similar to their widths. In one example, for TF elements that are 4 µm wide, the metallic elements may have widths of 0.4 µm and a separation of 0.4 µm.

[0057] As in Fig.As shown in Figure 31, each metallic conductor is coupled to an adjacent conductor at one end and another adjacent conductor at the opposite end. The metallic conductors formed at the edge of the group of conductors are coupled to interconnecting elements that connect the conductors to other groups of conductors. Therefore, a meandering electrical path is formed along the metallic conductors. In use, a current is passed through the conductors. This can cause the conductors to relatively quickly reach a predetermined temperature above the ambient temperature. Advantageously, the predetermined temperature may be approximately 100°C. Furthermore, this arrangement can be used with an on-chip temperature sensor in a closed-loop control system to maintain thin-film resistors at a substantially constant predetermined temperature.When such a sensor is calibrated at this given temperature, temperature drift of sensitivity or temperature drift of offset can be substantially eliminated or minimized, resulting in improved sensor output stability over ambient temperature.

[0058] One advantage of this arrangement is that the entire sensor can be heated to approximately the same temperature. If different parts of the sensor have different temperatures, mismatching between different resistive elements can occur. By keeping the sensor at the same temperature, the components can be better matched, and a more accurate sensor can result.

[0059] An example of fabricating a TF sensor 10 will now be discussed. The sensor is fabricated by first providing a substrate. An integrated circuit including a first component is provided over the substrate. The first component can be any other component suitable for integration on the same chip, such as a thin-film resistive sensor (e.g., an amplifier, analog-to-digital converter, etc.). The structure of this component includes metallic traces underlying the sensor. An insulating layer is formed over the first component. The metallic layer is then formed over the insulating layer. The metallic layer is then etched to create the stress-balancing structure. A second insulating layer is provided over the stress-balancing structure and is planarized by CMP (chemical mechanical polishing) to form a flat surface for the sensor.A resistive layer is then deposited over the second insulating layer. This is etched to create the thin-film resistive sensor. The interconnect elements are then formed from further metallization, such as gold. A passivation layer is then used to protect the structure from environmental influences, and openings in the passivation layer create the bond pads.

[0060] A stress-balancing layer is a layer that reduces the effects of stress caused by underlying or overlying elements. In this regard, although one goal of a stress-balancing layer is to equalize the impact load in an absolute sense, it is apparent that complete equalization is not possible in practice, and that the stress-balancing layer typically reduces the effects of the stress. Although specific stress-balancing structures have been described, any suitable arrangement of conductors or other stress-balancing elements may be implemented in the stress-balancing layer to thereby provide stress equalization for thin-film elements in an adjacent layer.Although embodiments may also discuss stress-balancing layers disposed beneath thin-film elements, each of the principles and advantages discussed herein may be applied to a stress-balancing layer disposed above thin-film elements, to stress-balancing layers both above and below thin-film elements, to more than one stress-balancing layer disposed beneath thin-film elements, and / or more than one stress-balancing layer disposed above thin-film elements. The stress-balancing layers discussed herein may be implemented in conjunction with any thin-film elements that could benefit from stress balancing.

[0061] Although the claims presented herein are in a single dependency format, it is to be understood that each claim may depend on any preceding claim of the same type, except where this is clearly not technically feasible.

[0062] Aspects of this disclosure may be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronic products, parts of electronic products such as electronic components assembled into an assembly, electronic test equipment, cellular communications infrastructure, etc.Examples of electronic devices may include, but are not limited to, precision instruments, medical devices, wireless devices, a mobile phone such as a smartphone, a telephone, a television, a computer monitor, a computer, a modem, a handheld computer, a laptop, a tablet computer, a portable computing device such as a smart watch, a personal digital assistant (PDA), a vehicle electronics system such as an automotive electronics system, a microwave oven, a refrigerator, a vehicle electronics system such as an automotive electronics system, a stereo system, a DVD player, a CD player, a digital music player such as an MP3 player, a radio, a camcorder, a camera, a digital camera, a portable memory chip, a washing machine, a dryer, a washer-dryer, a clock, etc.Furthermore, the electronic devices may include unfinished products.

[0063] Unless the context expressly suggests otherwise, throughout the specification and claims, the words "comprise," "comprising," "including," and the like are intended to be used in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is, to mean "including, but not limited to." The word "coupled," as generally used herein, refers to two or more elements that may be connected either directly or through one or more intermediate elements. Likewise, the word "connected," as generally used herein, refers to two or more elements that may be connected either directly or through one or more intermediate elements. Furthermore, the words "herein," "above," "hereinafter," and words of similar import, when used in this application, refer to this application as a whole and not to specific parts of this application.Where the context permits, words in the above detailed description of specific embodiments that use the singular or plural may also include the plural or singular, respectively. Where the context permits, the word "or" when referring to a list of two or more items may cover all of the following interpretations of the word: any of the items listed in the list, all of the items listed in the list, and any combination of the items listed in the list.

[0064] Furthermore, conditional language used herein, such as "may," "could," "may," "may," "may," "e.g.," and "such as," unless otherwise noted or understood in the context used, is generally intended to convey that certain embodiments include certain features, elements, and / or conditions, while other embodiments do not. Thus, such conditional language is not intended to imply that any elements, features, and / or conditions are in any way required for one or more embodiments.

[0065] Indeed, the novel devices, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes may be made to the form of the methods and systems described herein. For example, although elements and assemblies are illustrated in a given arrangement, alternative embodiments may perform similar functionality with other components and / or circuit topologies, and some elements may be removed, moved, added, subdivided, combined, and / or modified. Each of these elements or assemblies may be implemented in a variety of ways. Any suitable combination of the elements, assemblies, and / or operations of the various embodiments described above may be combined to create further embodiments.

Claims

[1] A thin-film magnetoresistive sensor (10) for use in an integrated circuit, the thin-film magnetoresistive sensor comprising: Thin film magnetoresistive elements (100, 102, 104, 106, 108) formed in a first layer of the thin film magnetoresistive sensor to form a circuit of the thin film magnetoresistive sensor; a stress compensation structure (60) comprising metallic stress compensation elements (174A-174E) formed in a second layer of the thin-film magnetoresistive sensor (10), wherein the metallic stress compensation elements (174A-174E) are arranged to compensate for a stress exerted on the thin-film magnetoresistive elements, and wherein the thin-film magnetoresistive elements (100, 102, 104, 106, 108) and the metallic stress compensation elements are arc-shaped. [2] Thin film magnetoresistive sensor (10) according to claim 1, wherein the metallic stress compensation elements are arranged in a periodic arrangement. [3] Thin film magnetoresistive sensor (10) according to claim 1 or 2, wherein the metallic stress compensation elements are elongated and arranged parallel to each other. [4] A thin film magnetoresistive sensor (10) according to claim 1, 2 or 3, wherein each thin film magnetoresistive element has a corresponding metallic stress equalizing element of substantially similar shape aligned therewith. [5] A thin-film magnetoresistive sensor (10) according to any one of the preceding claims, wherein the thin-film magnetoresistive elements and the metallic stress compensating elements are arranged in groups, and the thin-film magnetoresistive element groups are aligned with respective stress compensating element groups. [6] Thin-film magnetoresistive sensor (10) according to one of the preceding claims, wherein a stress balancing element of the metallic stress balancing elements extends under more than one thin-film magnetoresistive element and / or under more than one group of thin-film magnetoresistive elements. [7] A thin film magnetoresistive sensor (10) according to any one of the preceding claims, further comprising interconnecting elements, wherein the metallic stress balancing elements are coupled together by the interconnecting elements to form one or more electrical paths. [8] Thin film magnetoresistive sensor (10) according to one of the preceding claims, wherein the metallic stress compensation elements are designed to heat the device. [9] A thin film magnetoresistive sensor (10) according to any one of the preceding claims, wherein the stress balancing structure further comprises a third layer of the thin film resistive device comprising additional stress balancing elements. [10] A thin film magnetoresistive sensor (10) according to any one of the preceding claims, further comprising conductive interconnection elements configured to couple the thin film magnetoresistive elements together, and an insulating layer disposed between the first and second layers. [11] A monolithic integrated circuit with load balancing, the monolithic integrated circuit comprising: Thin-film magnetoresistive elements (100, 102, 104, 106, 108) arranged as a magnetoresistive sensor (10) in a first layer of the monolithic integrated circuit; metallic elements in a second layer of the monolithic integrated circuit, wherein the second layer is adjacent to the first layer and the metallic elements are arranged at positions of the second layer that correspond to positions of each of the thin-film magnetoresistive elements in the first layer, and wherein the thin-film magnetoresistive elements (100, 102, 104, 106, 108) and the metallic elements are arc-shaped. [12] A monolithic integrated circuit according to claim 11, wherein the metallic elements cover a region of the second layer similar to a region of the first layer covered by the thin film magnetoresistive elements (100, 102, 104, 106, 108). [13] A monolithic integrated circuit according to claim 11 or 12, wherein the metallic elements are arranged in a periodic pattern. [14] A monolithic integrated circuit according to any one of claims 11 to 13, wherein the metallic elements are adapted to heat the thin-film magnetoresistive elements (100, 102, 104, 106, 108) to approximately the same temperature. [15] Thin film magnetoresistive device comprising: a layer comprising a plurality of thin-film magnetoresistive elements (100, 102, 104, 106, 108) arranged as a magnetoresistive sensor (10); Means for reducing a difference in a stress applied to different thin-film magnetoresistive elements of the magnetoresistive sensor, and wherein the thin-film magnetoresistive elements (100, 102, 104, 106, 108) and the means are arc-shaped. [16] A thin film magnetoresistive device according to claim 15, wherein the means for reducing is included in a patterned metal layer, and wherein only one insulation layer is disposed between the patterned metal layer and the layer comprising the plurality of thin film magnetoresistive elements.

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