Laser writing apparatus and method for programming magnetoresistive devices - Patents.com

Abstract

In an embodiment of the present invention, a laser writing apparatus and method for programming a magnetoresistive device is disclosed. The apparatus includes a substrate, a magnetoresistive sensor, and a thermal control layer, arranged sequentially in a stack. A non-magnetic insulating layer for electrical isolation is provided between the magnetoresistive sensor and the thermal control layer. The magnetoresistive sensor is composed of a magnetoresistive sensing unit that is a multi-layer thin film stack structure including an antiferromagnetic layer. The laser writing programming apparatus is used with altered parameters of the thermal control layer and / or the magnetoresistive sensor during the laser writer programming stage to change the thermal gradient induced by the laser to the magnetoresistive sensor, thereby increasing or decreasing the temperature change of the magnetoresistive sensor at the same laser power, the film parameters used to do this include material composition and film thickness. Through the embodiment of the present invention, high precision laser programming of magnetoresistive sensors with improved magnetoresistive sensor manufacturability, improved magnetoresistive sensor noise performance, and improved magnetoresistive sensor detectability is obtained.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to the technical field of magnetic sensors, and in particular to a laser writing apparatus and method for programming magnetoresistive devices. [Background technology]

[0002] Magnetoresistive devices include linear sensors, angle sensors, switching sensors, gradient sensors, and various downstream magnetoresistive devices such as current sensors, financial magnetic heads, image sensors, electromagnetic encoders, and magnetoelectric isolators. Magnetoresistive sensors are integrated within magnetoresistive devices, and types of magnetoresistive sensors include tunneling magnetoresistance (TMR) sensors, giant magnetoresistance (GMR) sensors, and anisotropic magnetoresistance (AMR) sensors.

[0003] Currently, magnetoresistive sensors are fabricated by first performing magnetic field annealing on the whole wafer and then packaging it by flip-die packaging. Specifically, two identical dies are selected during packaging, one of the dies is rotated 180° relative to the other die, and then wire bonding is performed to obtain the magnetoresistive sensor.

[0004] However, this manufacturing method has the disadvantage that it requires the operation of the relative phase of the two wafers to continue, which makes it difficult to guarantee the accuracy, affects the performance of the magnetoresistive sensor, further reduces the detection accuracy of the magnetoresistive sensor, and increases the process complexity of the magnetoresistive sensor. Summary of the Invention [Means for solving the problem]

[0005] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention provide a laser writing apparatus and method for programming magnetoresistive devices for fabricating high precision magnetoresistive sensors.

[0006] An embodiment of the present invention provides a laser writing apparatus for programming magnetoresistive devices. The apparatus comprises a substrate, a magnetoresistive sensor, and a thermal control layer, arranged in a stack. A non-magnetic insulating layer for electrical isolation is provided between the magnetoresistive sensor and the thermal control layer. The magnetoresistive sensor is composed of a magnetoresistive sensing unit, which is a multi-layer thin film stack structure with an antiferromagnetic layer.

[0007] The laser writing apparatus for programming is configured to vary film layer parameters of the thermal control layer and / or the magnetoresistive sensor during the laser writing stage for programming to adjust the rate of change of temperature of the magnetoresistive sensor with the laser power and to increase or decrease the temperature written to the magnetoresistive sensor with the same laser power, the film layer parameters including at least one of the film layer material and the film layer thickness.

[0008] Based on the same inventive concept, an embodiment of the present invention also provides a laser writing method for programming a magnetoresistive device, which is implemented by a laser writing system for programming, the laser writing system for programming comprises a magnetic field generating device and a laser writing device for programming as described above, and the laser writing method for programming of the laser writing system for programming includes: Varying film layer parameters of the thermal control layer and / or the magnetoresistive sensor, including at least one of a film layer material and a film layer thickness, during the laser writing step for programming; Adjusting the rate of change of temperature of the magnetoresistive sensor with the laser power to write higher or lower temperatures to the magnetoresistive sensor with the same laser power.

[0009] In an embodiment of the present invention, a laser writing apparatus for programming comprises a substrate, a magnetoresistive sensor located on the substrate, and a thermal control layer located on the magnetoresistive sensor, a non-magnetic electrically insulating layer is provided between the thermal control layer and the magnetoresistive sensor, the magnetoresistive sensor comprises a magnetoresistive sensing unit, the magnetoresistive sensing unit is a multi-layer thin film stack structure comprising an antiferromagnetic layer, and a parameter of the thermal control layer is changed, thereby increasing or decreasing a rate of change of temperature of the corresponding magnetoresistive sensing unit array with the laser power at which writing is performed, and increasing or decreasing the temperature of the magnetoresistive sensing unit array when laser writing for programming is performed with the same laser power, thereby achieving high-precision laser writing for programming the magnetoresistive sensor, improving manufacturing defects of the magnetoresistive sensor, improving the performance of the magnetoresistive sensor, and further improving the detection accuracy of the magnetoresistive sensor.

[0010] In order to more clearly show the technical solutions according to the embodiments of the present invention or in the prior art, the accompanying drawings required for the description of the embodiments or the prior art are briefly introduced below. Obviously, the accompanying drawings in the following description are some specific embodiments of the present invention, but they can be expanded and extended to other structures and drawings for those skilled in the art according to the basic concepts of the device structure, driving method and manufacturing method disclosed and suggested by various embodiments of the present invention. Undoubtedly, these should be within the scope of the claims of the present invention. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram of a laser writing apparatus for programming a magnetoresistive device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of a multi-layer thin film stack of a laser writing apparatus for programming according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram of another multi-layer thin film stack structure. [Figure 4] FIG. 2 is a schematic diagram of yet another multi-layer thin film stack structure. [Diagram 5] 1 is a schematic diagram of a magnetoresistive sensor according to one embodiment of the present invention; [Figure 6] FIG. 1 is a schematic diagram of a single axis push-pull magnetoresistive sensor according to one embodiment of the present invention. [Figure 7A] Schematic diagram of laser writing for programming push-pull magnetoresistive sensors. [Figure 7B] The temperature profile of FIG. 7A. [Figure 8A] Schematic of the +d magnetic moment in a single-axis push-pull magnetoresistive sensor being written during thermal annealing. [Figure 8B] The temperature profile of FIG. 8A. [Figure 9A] Schematic of the +d magnetic moment in a single-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 9B] The temperature profile of FIG. 9A. [Figure 10A] Schematic of the +d magnetic moment in a single-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 10B] The temperature profile of FIG. 10A. [Figure 11A] Schematic of the -d magnetic moment in a single-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 11B] The temperature profile of FIG. 11A. [Figure 12A] Schematic of the -d magnetic moment in a single-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 12B] The temperature profile of FIG. 12A. [Figure 13A] Schematic of the +d1 magnetic moment in a dual-axis push-pull magnetoresistive sensor being written during thermal annealing. [Figure 13B] The temperature profile of FIG. 13A. [Figure 14A]FIG. 13 is a schematic diagram of the +d1 magnetic moment in a dual-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 14B] The temperature profile of FIG. 14A. [Figure 15A] Schematic of the +d1 magnetic moment in a dual-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 15B] The temperature profile of FIG. 15A. [Figure 16A] FIG. 11 is a schematic diagram of the -d1 magnetic moment in a dual-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 16B] The temperature profile of FIG. 16A. [Figure 17A] Schematic of the -d1 magnetic moment in a dual-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 17B] The temperature profile of FIG. 17A. [Figure 18A] Schematic of the +d2 magnetic moment in a two-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 18B] The temperature profile of FIG. 18A. [Figure 19A] Schematic of the +d2 magnetic moment in a two-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 19B] The temperature profile of FIG. 19A. [Figure 20A] Schematic of the -d2 magnetic moment in a two-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 20B] The temperature profile of FIG. 20A. [Figure 21A] Schematic of the -d2 magnetic moment in a two-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 21B] The temperature profile of FIG. 21A. [Figure 22A] Schematic of the +d1 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during thermal annealing. [Figure 22B] The temperature profile of FIG. 22A. [Figure 23A] FIG. 13 is a schematic diagram of the +d1 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 23B] The temperature profile of FIG. 23A. [Figure 24A] Schematic of the +d1 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 24B] The temperature profile of FIG. 24A. [Figure 25A] FIG. 11 is a schematic diagram of the -d1 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 25B] The temperature profile of FIG. 25A. [Figure 26A] FIG. 11 is a schematic diagram of the -d1 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 26B] The temperature profile of FIG. 26A. [Figure 27A] FIG. 11 is a schematic diagram of the +d2 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 27B] The temperature profile of FIG. 27A. [Figure 28A] Schematic of the +d2 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 28B] The temperature profile of FIG. 28A. [Figure 29A]FIG. 11 is a schematic diagram of the -d2 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 29B] The temperature profile of FIG. 29A. [Figure 30A] Schematic of the -d2 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 30B] The temperature profile of FIG. 30A. [Figure 31A] FIG. 13 is a schematic diagram of the +d3 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 31B] The temperature profile of FIG. 31A. [Figure 32A] Schematic of the +d3 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 32B] The temperature profile of FIG. 32A. [Figure 33A] Schematic of the -d3 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during global laser programming. [Figure 33B] The temperature profile of FIG. 33A. [Figure 34A] Schematic of the -d3 magnetic moment in a three-axis push-pull magnetoresistive sensor being written during local laser programming. [Figure 34B] The temperature profile of FIG. 34A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention are clearly and completely described below by embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the basic concepts disclosed and suggested by the embodiments of the present invention are within the scope of the present invention.

[0013] Referring to Fig. 1, a schematic diagram of a laser writing apparatus for programming a magnetoresistive device according to an embodiment of the present invention is shown. As shown in Fig. 1, the laser writing apparatus for programming includes a substrate 100, a magnetoresistive sensor 200, and a thermal control layer 300 arranged in a stack in sequence, a non-magnetic insulating layer 400 for electrical isolation is provided between the magnetoresistive sensor 200 and the thermal control layer 300, the magnetoresistive sensor 200 is composed of a magnetoresistive sensing unit which is a multi-layer thin film stack structure with an antiferromagnetic layer, and the laser writing apparatus for programming is configured to change the film layer parameters of the thermal control layer 300 and / or the magnetoresistive sensor 200 in the stage of laser writing for programming to adjust the rate of change of the temperature of the magnetoresistive sensor 200 with the laser power, and to increase or decrease the temperature written to the magnetoresistive sensor 200 with the same power, and the film layer parameters include at least one of a film layer material and a film layer thickness.

[0014] In this embodiment, optionally, the substrate 100 is a wafer, the magnetoresistive sensor 200 is composed of a magnetoresistive sensing unit that is a multi-layer thin film stack structure having an antiferromagnetic layer, and a non-magnetic insulating layer 400 is disposed between the magnetoresistive sensor 200 and the thermal control layer 300, and the non-magnetic insulating layer 400 serves to electrically insulate the magnetoresistive sensor 200 from the thermal control layer 300.

[0015] The process of laser writing for programming is the process of writing laser into the magnetoresistive sensor 200, thereby realizing the programming of the magnetic moment of the antiferromagnetic layer in the magnetoresistive sensor 200, and this process is also defined as the stage of laser writing for programming. In the stage of laser writing for programming, the change rate of the temperature T of the magnetoresistive sensor 200 during the heat transfer process changes with the magnitude of the laser power P writing into the magnetoresistive sensor 200, therefore, adjusting the magnitude of the laser power writing into the magnetoresistive sensor 200 can increase or decrease the change rate of the temperature of the magnetoresistive sensor 200 with the laser power, and the change rate of the temperature is dT / dP, thereby controlling the temperature writing into the magnetoresistive sensor 200 with the same laser power.

[0016] When the laser writes to the magnetoresistive sensor 200, the laser must pass through the thermal control layer 300. If the thermal control layer 300 changes in terms of material or thickness, the laser passes through the thermal control layer 300 with different film parameters at the same laser power, and the laser power that actually writes to the magnetoresistive sensor 200 also changes accordingly. Based on this, by increasing or decreasing the material or thickness of the thermal control layer 300, the same laser power that actually writes to the magnetoresistive sensor 200 can be adjusted, thereby controlling the heat transfer of the magnetoresistive sensor 200 by the action of the laser, so that the heat transfer of the magnetoresistive sensor 200 changes in response to the change in the laser power, thereby adjusting the rate of change of the temperature of the magnetoresistive sensor 200 with the laser power, thereby controlling the temperature that is written to the magnetoresistive sensor 200 with the same laser power, or vice versa.

[0017] According to the required temperature and / or rate of change of the magnetoresistive sensor 200 and certain film parameters of the thermal control layer 300, the required laser power is derived inversely, and the laser writing device for programming is driven to emit a laser according to the calculated laser power, and when the laser is written to the magnetoresistive sensor 200 through the thermal control layer 300, the laser power actually written to the magnetoresistive sensor 200 can adjust the magnetoresistive sensor 200 to the required rate of change of temperature and the required temperature.

[0018] In short, by increasing or decreasing the material or thickness of the thermal control layer 300 with the action of the same laser, the rate of change of temperature of the magnetoresistive sensor 200 can be increased or decreased with changes in the magnitude of the laser power, thereby adjusting the temperature of the magnetoresistive sensor 200, such as increasing or decreasing the temperature of the magnetoresistive sensor 200, with the same laser power, thereby programming the magnetic moment of the antiferromagnetic layer in the magnetoresistive sensor 200.

[0019] Similarly, the magnetoresistive sensing unit can be seen to be a multi-layer thin film stack structure with an antiferromagnetic layer. When the laser writes into the magnetoresistive sensor 200, on the laser propagation path, the laser passes through each film layer located on the antiferromagnetic layer in the magnetoresistive sensor 200 in succession, and then enters the antiferromagnetic layer. Then, if the material or thickness of at least one film layer located on the antiferromagnetic layer in the magnetoresistive sensor 200 and through which the laser passes changes, such as increasing or decreasing, the laser power that actually writes into the magnetoresistive sensor 200 also changes accordingly, so that the heat transfer of the magnetoresistive sensor 200 changes in response to the change in the laser power, thereby adjusting the rate of change of the temperature of the magnetoresistive sensor 200 with the laser power, and further controlling the temperature that is written into the magnetoresistive sensor 200 with the same laser power, programming the magnetic moment of the antiferromagnetic layer in the magnetoresistive sensor 200.

[0020] Optionally, the wavelength range of the laser is between 100 nm and 3000 nm. The laser power is adjusted within this range to control the temperature of the magnetoresistive sensor. In other embodiments, further optionally, the thermal control layer is located within the multi-layer thin film stack structure.

[0021] In an embodiment of the present invention, a laser writing apparatus for programming comprises a substrate, a magnetoresistive sensor located on the substrate, and a thermal control layer located on the magnetoresistive sensor, a non-magnetic electrically insulating layer is provided between the thermal control layer and the magnetoresistive sensor, the magnetoresistive sensor comprises a magnetoresistive sensing unit, the magnetoresistive sensing unit is a multi-layer thin film stack structure comprising an antiferromagnetic layer, and a parameter of the thermal control layer is changed, thereby increasing or decreasing a rate of change of temperature of the corresponding magnetoresistive sensing unit array with a laser power at which writing is performed, and can increase or decrease the temperature of the magnetoresistive sensing unit array when the laser writing for programming is performed with the same laser power, thereby achieving high-precision laser writing for programming the magnetoresistive sensor, improving manufacturing defects of the magnetoresistive sensor, improving the performance of the magnetoresistive sensor, and further improving the detection accuracy of the magnetoresistive sensor.

[0022] As an example, based on the basic solution described above, optionally, the magnetoresistive sensor is a giant magnetoresistance (GMR) sensor, a tunnel magnetoresistance (TMR) sensor, or an anisotropic magnetoresistance (AMR) sensor. Optionally, in the direction from the substrate to the thermal control layer, the multilayer thin film stack structure comprises a seed layer, an antiferromagnetic layer, a free layer, a top electrode layer, and a cap layer, which are sequentially arranged in a stack, and a first insulating layer is provided between the substrate and the seed layer, and the laser writing device for programming is configured to change the material of at least one film layer among the thermal control layer, the first insulating layer, the seed layer, the top electrode layer, and the cap layer to increase or decrease the temperature at which the magnetoresistive sensor is written with the same laser power, and / or the laser writing device for programming is configured to change the thickness of at least one film layer among the thermal control layer, the first insulating layer, the seed layer, the top electrode layer, and the cap layer to increase or decrease the temperature at which the magnetoresistive sensor is written with the same laser power.

[0023] Referring to FIG. 2, a schematic diagram of a multi-layer thin film stack of a laser writing device for programming according to an embodiment of the present invention is shown. As shown in FIG. 2, optionally, the magnetoresistive sensor 200 is a GMR or TMR sensor, and the magnetoresistive sensor 200 comprises a SAF reference layer 204. In this embodiment, the laser writing device for programming comprises a substrate 100, a magnetoresistive sensor 200 located on the substrate 100, and a thermal control layer (heat control) 300 located on the magnetoresistive sensor 200. It should be understood that a non-magnetic insulating layer (not shown) is further provided between the magnetoresistive sensor 200 and the thermal control layer 300. Optionally, the substrate 100 is a wafer, but is not limited thereto.

[0024] The magnetoresistive sensor 200 is composed of one or more magnetoresistive sensing units, which are multi-layer thin film stack structures. In the direction from the substrate 100 to the thermal control layer 300, the multi-layer thin film stack structure sequentially comprises a first insulating layer 201, a seed layer (Seed) 202, an antiferromagnetic layer (AFL) 203, an SAF reference layer 204, a barrier layer (BL) 205, a free layer (FL) 206, a top electrode layer (TE) 207, and a cap layer (CAP) 208. Among them, the SAF reference layer 204 comprises a pinned layer (PL) 204a, a metal layer (ML) 204b, and a reference layer (RL) 204c.

[0025] Referring to Fig. 3, a schematic diagram of a multi-layer thin film stack of another laser writing apparatus for programming according to an embodiment of the present invention is shown. As shown in Fig. 3, optionally, the magnetoresistive sensor 200 is a GMR or TMR sensor. The difference from Fig. 2 is that in Fig. 3, the SAF reference layer of the magnetoresistive sensor 200 comprises a reference layer (RL) 204.

[0026] With respect to the magnetoresistive sensor 200 shown in Figures 2 and 3, if the barrier layer (BL) 205 is a film layer made of a metallic material, optionally including any one of Ta, Ru, and Cu or an alloy, the magnetoresistive sensing unit is a GMR sensing unit, and if the barrier layer (BL) 205 is a film layer made of a non-metallic material, optionally including at least one of Al2O3 and MgO, the magnetoresistive sensing unit is a TMR sensing unit.

[0027] Referring to Fig. 4, a schematic diagram of a multi-layer thin film stack of yet another laser writing apparatus for programming according to an embodiment of the present invention is shown. As shown in Fig. 4, optionally, the magnetoresistive sensor 200 is an AMR sensor. The difference from Fig. 2 is that in Fig. 4, the magnetoresistive sensor 200 does not include a SAF reference layer and a barrier layer (BL).

[0028] As an example, based on the basic solution described above, optionally, the magnetoresistive sensor is a push-pull magnetoresistive sensor, the push-pull magnetoresistive sensor is composed of a push magnetoresistive sensing unit array and a pull magnetoresistive sensing unit array, and both the push magnetoresistive sensing unit array and the pull magnetoresistive sensing unit array are composed of magnetoresistive sensing units. The push-pull magnetoresistive sensor is a full-bridge structure, a half-bridge structure, or a quasi-bridge structure.

[0029] Referring to FIG. 5, a schematic diagram of a magnetoresistive sensor according to an embodiment of the present invention is shown. As shown in FIG. 5, the magnetoresistive sensor is located between a substrate 100 and a thermal control layer. Optionally, the magnetoresistive sensor is a push-pull magnetoresistive sensor 200. In this embodiment, the push-pull magnetoresistive sensor 200 comprises a push magnetoresistive unit array and a pull magnetoresistive unit array, where the push magnetoresistive unit array is composed of a push magnetoresistive sensing unit 200a and the pull magnetoresistive unit array is composed of a pull magnetoresistive sensing unit 200b. Although the magnetoresistive sensor shown in FIG. 5 is shown as a GMR / TMR sensor with a SAF reference layer as shown in FIG. 2, the analysis process and its results are equally applicable to other magnetoresistive sensors with different SAF reference layers or no SAF reference layer.

[0030] The push magnetoresistive sensing unit 200a and the pull magnetoresistive sensing unit 200b are located on the same substrate 100, and the thermal control layer located on the push magnetoresistive sensing unit 200a is the push thermal control layer 300a, and the thermal control layer located on the pull magnetoresistive sensing unit 200b is the pull thermal control layer 300b. The antiferromagnetic layer 203a in the multi-layer thin film stack structure of the push magnetoresistive sensing unit 200a and the antiferromagnetic layer 203b in the multi-layer thin film stack structure of the pull magnetoresistive sensing unit 200b have opposite magnetic moment directions, the antiferromagnetic layer 203a in the push magnetoresistive sensing unit 200a has a magnetic moment direction +d, and the antiferromagnetic layer 203b in the pull magnetoresistive sensing unit 200b has a magnetic moment direction -d, where d can be the X-direction, the Y-direction, or the Z-direction.

[0031] The following film layers with the same names in the push magnetoresistive sensing unit 200a and the pull magnetoresistive sensing unit 200b have the same materials and properties. Specifically, the pinned layers (PL) 204a in the push magnetoresistive sensing unit 200a and the pull magnetoresistive sensing unit 200b have the same materials and properties, the metal layers (ML) 204b therein have the same materials and properties, the reference layers (RL) 204c therein have the same materials and properties, the barrier layers (BL) 205 therein have the same materials and properties, and the free layers (FL) 206 therein have the same materials and properties.

[0032] To create a heat transfer difference between the push magnetoresistive sensing unit 200a and the pull magnetoresistive sensing unit 200b in the magnetoresistive sensor with the same laser power, at least one of the following film layer design schemes may be implemented. 1) The cap layer (CAP) of the push magnetoresistive sensing unit 200a and the cap layer 208 of the pull magnetoresistive sensing unit 200b use different materials and / or thicknesses. 2) The top electrode layer (TE) of the push magnetoresistive sensing unit 200a and the top electrode layer 207 of the pull magnetoresistive sensing unit 200b use different materials and / or thicknesses. 3) The seed layer (Seed) of the push magnetoresistive sensing unit 200a and the seed layer 202 of the pull magnetoresistive sensing unit 200b use different materials and / or thicknesses. 4) The first insulating layer of the push magnetoresistive sensing unit 200a and the first insulating layer 201 of the pull magnetoresistive sensing unit 200b use different materials and / or thicknesses. 5) The push thermal control layer 300a of the push magnetoresistive sensing unit 200a and the pull thermal control layer 300b of the pull magnetoresistive sensing unit 200b use different materials and / or thicknesses.

[0033] Any one or more combinations of the above film design methods 1) to 5) can be used in the process of laser writing for programming to realize a heat transfer difference between the push magnetoresistance sensing unit 200a and the pull magnetoresistance sensing unit 200b when writing with the same laser power, and finally realize a temperature difference between the antiferromagnetic layer (AFL) of the push magnetoresistance sensing unit 200a and the antiferromagnetic layer (AFL) of the pull magnetoresistance sensing unit 200b, thereby changing the process and parameters of laser writing for programming and realizing separate writing of the magnetic moments of the antiferromagnetic layers.

[0034] By way of example, optionally, the thermal control layer comprises a non-magnetic low laser absorption coefficient material or a high laser absorption coefficient material, the low laser absorption coefficient material comprises at least one of tantalum, titanium, copper, molybdenum, gold, silver, aluminum, platinum, and tin, and the high laser absorption coefficient material comprises at least one of zirconium oxide, titanium oxide, carbon film, phosphate, and aluminum titanium nitride. Optionally, the thermal control layer comprises a carbon black, a non-magnetic laser absorbing resin, or a non-magnetic laser absorbing coating.

[0035] The thermal control layer may be an air layer. Alternatively, the thermal control layer is a non-magnetic material. The non-magnetic material constituting the thermal control layer includes a laser low absorption coefficient material, such as at least one of Ta, Ti, Cu, Mo, Au, Ag, Al, Mo, Pt, and Sn. Alternatively, the non-magnetic material constituting the thermal control layer includes a laser high absorption coefficient material, such as at least one of ZrO, TiO, carbon film, phosphate, and TiAlN. When the thermal control layer is made of a non-magnetic material, electrical isolation may be achieved between the thermal control layer and the magnetoresistive sensor using an electrically insulating material, i.e., a non-magnetic insulating layer is disposed between them. In a further option, the material constituting the thermal control layer includes carbon black, a laser absorbing resin, or a laser absorbing coating, and the laser absorbing resin and the laser absorbing coating include a mixture of polymer, carbon black, and oxide particles.

[0036] Optionally, the push-pull magnetoresistive sensor is a single-axis push-pull magnetoresistive sensor, a dual-axis push-pull magnetoresistive sensor, or a triple-axis push-pull magnetoresistive sensor.

[0037] Optionally, the push-pull magnetoresistive sensor is a single-axis push-pull magnetoresistive sensor. For example, the magnetoresistive sensor is an X-axis push-pull magnetoresistive sensor comprising a +X magnetoresistive sensing unit array and a -X magnetoresistive sensing unit array. Alternatively, the +X and -X magnetoresistive sensing unit arrays and the magnetic flux concentrator form a Y-axis push-pull magnetoresistive sensor. Alternatively, the +X and -X magnetoresistive sensing unit arrays and the magnetic flux concentrator form a Z-axis push-pull magnetoresistive sensor. Alternatively, the +Y and -Y magnetoresistive sensing unit arrays and the magnetic flux concentrator form a Z-axis push-pull magnetoresistive sensor.

[0038] Optionally, the push-pull magnetoresistive sensor is a biaxial push-pull magnetoresistive sensor. For example, the magnetoresistive sensor is an XY biaxial push-pull magnetoresistive sensor comprising +X, -X, +Y, and -Y magnetoresistive sensing unit arrays. Alternatively, the +X, -X, +Z, and -Z magnetoresistive sensing unit arrays form an XZ biaxial push-pull magnetoresistive sensor. Alternatively, the +Y, -Y, +Z, and -Z magnetoresistive sensing unit arrays form a YZ biaxial push-pull magnetoresistive sensor. Alternatively, the +X, -X, +Y, and -Y magnetoresistive sensing unit arrays and the magnetic flux concentrator form a Z-axis compound push-pull magnetoresistive sensor.

[0039] Optionally, the push-pull magnetoresistive sensor is a three-axis push-pull magnetoresistive sensor, for example an XYZ three-axis push-pull magnetoresistive sensor comprising +X, -X, +Y, -Y, +Z and -Z magnetoresistive sensing unit arrays.

[0040] In another embodiment, further optionally, the +Z and -Z magnetoresistive sensing unit arrays form a Z-axis push-pull magnetoresistive sensor, and the antiferromagnetic layers in the magnetoresistive sensing units of the +Z magnetoresistive sensing unit array have a magnetization direction +Z, and the antiferromagnetic layers in the magnetoresistive sensing units of the -Z magnetoresistive sensing unit array have a magnetization direction -Z.

[0041] Referring to FIG. 6, a schematic diagram of a single-axis push-pull magnetoresistive sensor according to an embodiment of the present invention is shown. In this embodiment, the single-axis magnetoresistive sensor includes four electrodes, namely Vcc, GND, V+, and V- electrodes, and further includes four magnetoresistive sensing unit arrays 200a to 200d arranged in a 2*2 array, and the antiferromagnetic layers of the four magnetoresistive sensing unit arrays 200a to 200d have two opposite magnetic moment directions d1 and d2. Among them, the two magnetoresistive sensing unit arrays 200a and 200d arranged diagonally in the array act as pull magnetoresistive sensing unit arrays, and the antiferromagnetic layers of the two arrays have the same magnetic moment direction d2, and the two magnetoresistive sensing unit arrays 200b and 200c arranged diagonally in the array act as push magnetoresistive sensing unit arrays, and the antiferromagnetic layers of the two arrays have the same magnetic moment direction d1. The single-axis magnetoresistive sensor further includes push thermal control layers 302 and 303 covering the two push magnetoresistive sensing unit arrays 200b and 200c, respectively, and pull thermal control layers 301 and 304 covering the two pull magnetoresistive sensing unit arrays 200a and 200d, respectively, where the push thermal control layers 302 and 303, and the pull thermal control layers 301 and 304 are all air layers.

[0042] In other embodiments, the push magnetoresistive sensing unit arrays may be further optionally arranged in the same row or in the same column, and the pull magnetoresistive sensing unit arrays may be further optionally arranged in the same row or in the same column accordingly. Alternatively, the push magnetoresistive sensing unit array and the pull magnetoresistive sensing unit array may further optionally form a 1*4 array or a 4*1 array, and the two push magnetoresistive sensing unit arrays may be arranged adjacently or crosswise.

[0043] 6 shows a die diagram of a single-axis magnetoresistive sensor. In another embodiment, and further optionally, the magnetoresistive sensor is a dual-axis magnetoresistive sensor comprising a push magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction d1, a pull magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction -d1, a push magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction d2, and a pull magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction -d2.

[0044] In another embodiment, as a further option, the magnetoresistive sensor is a three-axis magnetoresistive sensor comprising a push magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction d1, a pull magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction -d1, a push magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction d2, a pull magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction -d2, a push magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction d3, and a pull magnetoresistive sensing unit array with an antiferromagnetic layer having a magnetic moment direction -d3.

[0045] Among them, the magnetoresistive sensor has a full-bridge structure in each dimension, correspondingly comprising two push magnetoresistive sensing unit arrays and two pull magnetoresistive sensing unit arrays. Alternatively, the magnetoresistive sensor has a half-bridge structure in each dimension, correspondingly comprising one push magnetoresistive sensing unit array and one pull magnetoresistive sensing unit array. Alternatively, the magnetoresistive sensor has a quasi-bridge structure in each dimension, correspondingly comprising one push magnetoresistive sensing unit array and one pull magnetoresistive sensing unit array. In fact, regardless of the combined arrangement of the magnetoresistive sensor, the magnetic moment can be written into the antiferromagnetic layer by laser writing for programming in the same manner.

[0046] Based on the same inventive concept, an embodiment of the present invention provides a laser writing method for programming a magnetoresistive device, which is implemented based on a laser writing system for programming, the laser writing system for programming comprises a magnetic field generating device and the laser writing apparatus for programming according to any one of the above embodiments, and the laser writing method for programming of the laser writing system for programming comprises: Varying film layer parameters of the thermal control layer and / or the magnetoresistive sensor, including at least one of a film layer material and a film layer thickness, during the laser writing step for programming; Adjusting the rate of change of temperature of the magnetoresistive sensor with the laser power to write higher or lower temperatures to the magnetoresistive sensor with the same laser power.

[0047] Optionally, the magnetoresistive sensor is a push-pull magnetoresistive sensor, the push-pull magnetoresistive sensor comprising a group of push magnetoresistive sensing unit arrays and pull magnetoresistive sensing unit arrays, the antiferromagnetic layer of the push magnetoresistive sensing unit array has a magnetic moment direction +di, and the antiferromagnetic layer of the pull magnetoresistive sensing unit array has a magnetic moment direction -di, where i is a positive integer and 1≦i≦3.

[0048] The laser writing method for programming further includes writing a magnetic moment to an antiferromagnetic layer of the push-pull magnetoresistive sensor, which includes writing a magnetic moment direction +di of the antiferromagnetic layer to the push magnetoresistive sensing unit array and writing a magnetic moment direction -di of the antiferromagnetic layer to the pull magnetoresistive sensing unit array.

[0049] Optionally, writing a magnetic moment direction +di of the antiferromagnetic layer to the magnetoresistive sensing unit array comprises: Setting the magnetic field annealing output to Poven and the temperature to Tw, and performing magnetic field thermal annealing in the +di direction on the wafer so that the antiferromagnetic layer of each magnetoresistive sensing unit array has a magnetic moment direction of +di, or setting the laser output to P(+di) and the temperature to Tdi, and generating a magnetic field in the +di direction so as to write a magnetic moment in the +di direction into the antiferromagnetic layer of the push magnetoresistive sensing unit array.

[0050] Optionally, writing the magnetic moment direction -di of the antiferromagnetic layer into the pull magnetoresistive sensing unit array Setting the magnetic field annealing output to Poven and the temperature to Tw, and performing magnetic field thermal annealing in the -di direction on the wafer so that the antiferromagnetic layer of each magnetoresistive sensing unit array has a magnetic moment direction of -di, or setting the laser output to P(-di) and the temperature to Tdi, and generating a magnetic field in the -di direction so as to write a magnetic moment in the -di direction into the antiferromagnetic layer of the pull magnetoresistive sensing unit array.

[0051] Optionally, Td1 < Td2 < Td3.

[0052] Optionally, Tb < Td1 < Td2 < Td3 < Td, where Tb is the writing temperature of the magnetoresistive sensing unit array and Td is the damage temperature of the magnetoresistive sensing unit array. It should be understood that d1, d2, and d3 represent any one of the x-axis, y-axis, and z-axis, and include axial directions that are positive and negative with respect to each other.

[0053] The three-axis magnetic field writing system, i.e., the laser writing system for programming, is as shown in Fig. 7A. The system includes an X-axis coil 5(1) for generating an X magnetic field 6 and a -X magnetic field 6(1), a Z-axis coil 5(5) for generating a Z magnetic field 6(4) and a -Z magnetic field 6(5), a Y-axis coil for generating a Y magnetic field 6(2) and a -Y magnetic field 6(3), a d1 push / pull magnetoresistive sensing unit array 11 having a magnetic moment direction d1, and an adjacent d2 push / pull magnetoresistive sensing unit array 12 having a magnetic moment direction d2, where corresponding 41 and 42 are a d1 push / pull thermal control layer and a d2 push / pull thermal control layer, respectively.

[0054] During laser writing for programming, the laser spot 8 is written on the surface of the thermal control layers 41 and 42 along the direction 9, so that the d1 push / pull magnetoresistive sensing unit array 11 is written in the magnetic field 13(0), and the temperature of the writing process is as shown in FIG. 7B. When writing to the d1 push / pull magnetoresistive sensing unit array with the laser power P(+d1), its magnetoresistive sensing unit has a temperature Tw(d1)|P(+d1), where Tw is between the blocking temperature Tb of the antiferromagnetic (AF) layer and the damage temperature Td of the magnetoresistive sensing unit. A magnetic field generator is switched on to generate a magnetic field in the direction d1, so that a magnetic moment can be written to the antiferromagnetic layer during cooling.

[0055] Furthermore, since there is no need to use a large gap thermal isolation (>50um) between adjacent d2 magnetoresistance sensing units and d1 magnetoresistance sensing unit arrays, adjacent d2 magnetoresistance sensing units have the opportunity to be heated at a temperature Tw(d2)|P(+d1). The temperature depends on the heat transfer of d2 magnetoresistance sensing units and d1 magnetoresistance sensing units, and can be optionally lower than Tb, and actually between Tb and Td. Based on this, optionally, the laser has a wavelength within a range of 100nm to 3000nm, which can meet the scanning sequence of laser writing for programming, and the design of heat transfer between magnetoresistance sensing unit arrays.

[0056] As an example, writing the magnetic moment directions +d and -d of the antiferromagnetic layer of a single-axis push-pull magnetoresistive sensor may include two steps: 1) writing the magnetic moment direction +d of the antiferromagnetic layer to the +d-push magnetoresistive sensing unit array; and 2) writing the magnetic moment direction -d of the antiferromagnetic layer to the -d-pull magnetoresistive sensing unit array.

[0057] Optionally, 1) writing the magnetic moment direction +d of the antiferromagnetic layer to the +d-push magnetoresistive sensing unit array includes the following three methods:

[0058] Method I: As shown in Fig. 8A, a uniaxial push-pull magnetoresistive sensor is installed in the magnetic field annealing furnace 7. The thermal output of the magnetic field annealing furnace 7 is set to Poven, the temperature is set to Tw, and the magnetic field generator 5(1) is used to generate a magnetic field 6 in the +d direction. The wafer undergoes +d direction magnetic thermal annealing. As a result, the +d push magnetoresistive sensing unit array 11 and the -d pull magnetoresistive sensing unit array 12 located on the substrate 3 obtain a +d magnetic moment 13(0), and the push thermal control layer 41 and the pull thermal control layer 42 do not function. At this point, the temperature profile of the uniaxial push-pull magnetoresistive sensor is as shown in Fig. 8B, Tw(+d)|P(oven) = Tw(-d)|P(oven), that is, the temperature rise Tw(+d)|P(oven) of the +d push magnetoresistive sensing unit array 11 is equal to the temperature rise Tw(-d)|P(oven) of the -d pull magnetoresistive sensing unit array 12, and the temperature of the magnetoresistive sensing unit array is between Tb and Td.

[0059] Method II: As shown in Fig. 9A, a uniaxial push-pull magnetoresistive sensor is installed in the magnetic field generator 5(1). The magnetic field generator 5(1) generates a magnetic field 6 in the +d direction. The laser output of the magnetic field generator 5(1) is set to P(+d), and the temperature is set to Tw. Then, the laser spot 8 generated by the magnetic field generator 5(1) scans the +d push magnetoresistive sensing unit array 11 and the -d pull magnetoresistive sensing unit array 12 along the direction 9. As a result, each magnetoresistive sensing unit array located on the substrate 3 is written with a +d magnetic field 13(0), and the push thermal control layer 41 and the pull thermal control layer 42 do not function. At this point, the temperature profile of the uniaxial push-pull magnetoresistive sensor is as shown in Fig. 9B, Tb < Tw(+d)|P(+d) < Tw(-d)|P(+d) < Td, that is, under the action of the same laser output P(+d), the temperature rise Tw(+d)|P(+d) of the +d push magnetoresistive sensing unit array 11 is slower than the temperature rise Tw(-d)|P(+d) of the -d pull magnetoresistive sensing unit array 12, and the temperature of the magnetoresistive sensing unit array is between Tb and Td.

[0060] Method III: As shown in FIG. 10A, a uniaxial push-pull magnetoresistive sensor is installed in the magnetic field generating device 5(1), the magnetic field generating device 5(1) generates a magnetic field 6 in the +d direction, the laser output of the magnetic field generating device 5(1) is set to P(+d), the temperature is set to Tw, then the laser spot 8 generated by the magnetic field generating device 5(1) scans the +d push magnetoresistive sensing unit array 11 along the direction 9, as a result, the +d push magnetoresistive sensing unit array 11 located on the substrate 3 is written with the magnetic field 13(0) in the +d direction, the push thermal control layer 41 and the pull thermal control layer 42 do not function, at this point, the temperature profile of the uniaxial push-pull magnetoresistive sensor is as shown in FIG. 12, the +d push magnetoresistive sensing unit array 11 has a temperature rise Tw(+d)|P(+d), and the -d pull magnetoresistive sensing unit array 12 has a temperature rise Tw(-d)|P(+d) which is the room temperature Tr.

[0061] Optionally, 2) writing the magnetic moment direction -d of the antiferromagnetic layer into the -d pull magnetoresistive sensing unit array includes the following three methods.

[0062] Method I: As shown in FIG. 11A, when the laser spot 8 scans the +d push magnetoresistive sensing unit array 11 and the -d pull magnetoresistive sensing unit array 12 along the direction 9 and the laser output of the magnetic field generating device 5(1) is set to P(-d) and the temperature is set to Tw, then the magnetic field generating device 5(1) generates a magnetic field 6(0) in the -d direction, and the -d pull magnetoresistive sensing unit array 12 is written with the magnetic field 13(1) in the -d direction. At this point, as shown in FIG. 11B, in the temperature profile of the uniaxial push-pull magnetoresistive sensor, Tr < Tw(+d)|P(-d) < Tb < Tw(-d)|P(-d) < Td, where Tr is the room temperature, the +d pull magnetoresistive sensing unit array 11 has a temperature rise Tw(+d)|P(-d), and the -d pull magnetoresistive sensing unit array 12 has a temperature rise Tw(-d)|P(-d).

[0063] Method II: As shown in FIG. 12A, the laser spot 8 scans the -d pull magnetoresistive sensing unit array 12 along the direction 9. When the laser output of the magnetic field generating device 5(1) is set to P(-d) and the temperature is set to Tw, then the magnetic field generating device 5(1) generates a -d direction magnetic field 6(0), and the -d pull magnetoresistive sensing unit array 12 is written with a -d direction magnetic field 13(1). The magnetic moment of the adjacent +d push magnetoresistive sensing unit array 11 is not affected, and its temperature profile is as shown in FIG. 12B, where Tr < Tw(+d)|P(-d) < Tb < Tw(-d)|P(-d) < Td, and the temperature is maintained at Tw(+d)|P(-d). The -d pull magnetoresistive sensing unit array 12 has a temperature rise Tw(-d)|P(-d), where Tr is room temperature.

[0064] By way of example, writing the magnetic moment directions +d and -d of the antiferromagnetic layer of a biaxial push-pull magnetoresistive sensor may include four steps, namely: 1) writing the magnetic moment direction +d1 of the antiferromagnetic layer to the +d1 push magnetoresistive sensing unit array; 2) writing the magnetic moment direction -d1 of the antiferromagnetic layer to the -d1 pull magnetoresistive sensing unit array; 3) writing the magnetic moment direction +d2 of the antiferromagnetic layer to the +d2 push magnetoresistive sensing unit array; and 4) writing the magnetic moment direction -d2 of the antiferromagnetic layer to the -d2 pull magnetoresistive sensing unit array.

[0065] Optionally, 1) writing the magnetic moment direction +d1 of the antiferromagnetic layer to the +d1 push magnetoresistive sensing unit array includes the following three methods.

[0066] Method I: As shown in FIG. 13A, a magnetic field annealing furnace 7 is used, the thermal output of the magnetic field annealing furnace 7 is set to Poven, the temperature is set to Tw, and its magnetic field generating device 5(1) is used to generate a magnetic field 6 in the +d1 direction. As a result, the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, as well as the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14 located on the substrate 3, obtain a magnetic moment 13(0) in the +d1 direction. The +d1 push thermal control layer 41, the -d1 pull thermal control layer 42, the +d2 push thermal control layer 43, and the -d2 thermal control layer 44 do not function, and its temperature profile is as shown in FIG. 13B. The +d1 push magnetoresistive sensing unit array 11 has a temperature rise Tw(+d1)|P(oven), the -d1 pull magnetoresistive sensing unit array 12 has a temperature rise Tw(-d1)|P(oven), the +d2 push magnetoresistive sensing unit array 13 has a temperature rise Tw(+d2)|P(oven), and the -d2 pull magnetoresistive sensing unit array 14 has a temperature rise Tw(-d2)|P(oven). These satisfy the relationship Tb < Tw(+d1)|P(oven) = Tw(-d1)|P(oven) = Tw(+d2)|P(oven) = Tw(-d2)|P(oven) < Td, and the temperature of the magnetoresistive sensing unit array is between Tb and Td.

[0067] Method II: As shown in FIG. 14A, when the magnetic field generating device 5(1) generates a magnetic field 6 in the +d1 direction, the laser output of the magnetic field generating device 5(1) is set to P(+d1), and the temperature is set to Tw, the laser spot 8 generated by the magnetic field generating device 5(1) scans the +d1 and +d2 push magnetoresistive sensing unit arrays 11 and 13 and the -d1 and -d2 pull magnetoresistive sensing unit arrays 12 and 14 along the direction 9. When the magnetic field generating device 5(1) generates a magnetic field 6 in the +d1 direction, all the magnetoresistive sensing unit arrays 11 to 14 are written with the magnetic field 13(0) in the +d1 direction, and its temperature profile is as shown in FIG. 14B, where Tb < Tw(+d1)|P(+d1) < T(-d1)|P(+d1) < Tw(+d2)|P(+d1) < Tw(-d2)|P(+d1) < Td. That is, due to the action of the same laser output P(+d1), the temperature rises Tw(+d1)|P(+d1) of the +d1 push magnetoresistive sensing unit array 11, the temperature rise Tw(-d1)|P(+d1) of the -d1 pull magnetoresistive sensing unit array 12, the temperature rise Tw(+d2)|P(+d1) of the +d2 push magnetoresistive sensing unit 13, and the temperature rise Tw(-d2)|P(+d1) of the -d2 pull magnetoresistive sensing unit 14 are arranged in ascending order from slow to fast.

[0068] Method III: As shown in FIG. 15A, when the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 along the direction 9, the magnetic field generating device 5(1) generates a magnetic field 6 in the +d1 direction, and the +d1 push magnetoresistive sensing unit array 11 is written with the magnetic field 13(0) in the +d1 direction. Its temperature profile is as shown in FIG. 15B. The +d1 push magnetoresistive sensing unit array 11 has a temperature Tw(+d1)|P(+d1), and the adjacent -d1 pull magnetoresistive sensing unit array 12 has a temperature Tw(-d1)|P(+d1), where Tw(+d1)|P(+d1) is slower than Tw(-d1)|P(+d1), which can result in writing the magnetic moment to the magnetoresistive sensing unit.

[0069] Optionally, 2) writing the magnetic moment direction -d1 of the antiferromagnetic layer to the -d1 pull magnetoresistive sensing unit array includes the following two methods:

[0070] Method I: As shown in FIG. 16A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, as well as the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14 along the direction 9, the magnetic field generator 5 (1) generates a magnetic field 6 (0) in the direction -d1, the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13, and the -d2 pull magnetoresistive sensing unit array 14 are all written in the direction -d1 magnetic field 13 (1), and the temperature profile of the magnetoresistive sensor is as shown in FIG. 16B. <Tw(+d1)|P(-d1)<Tb<Tw(-d1)|P(-d1)<Tw(+d2)|P(-d1)<Tw(-d2)|P(-d1)<Tdである。

[0071] Method II: As shown in FIG. 17A, when the laser spot 8 scans the -d1 pull magnetoresistive sensing unit array 12 along the direction 9, and the magnetic field generator 5 (1) generates a magnetic field 6 (0) in the direction -d1, only the -d1 pull magnetoresistive sensing unit array 12 is written in the direction -d1 magnetic field 13 (1), the magnetic moment of the adjacent +d1 push magnetoresistive sensing unit array 11 is not affected, and the magnetic moment of the adjacent +d2 push magnetoresistive sensing unit array 13 may be affected, and the temperature profile is as shown in FIG. 17B, and the Tr <Tw(+d1)|P(-d1)<Tb<Tw(-d1)|P(-d1)<Tw(+d2)|P(-d1)<Tdである。

[0072] Optionally, 3) writing the magnetic moment direction +d2 of the antiferromagnetic layer to the +d2 push magnetoresistive sensing unit array includes the following two methods:

[0073] Method I: As shown in FIG. 18A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, as well as the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14 along the direction 9, the magnetic field generator (not marked here) generates a magnetic field in the direction +d2 6(2), and only the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14 are written in the direction +d2 magnetic field 13(2), and the temperature profile of the magnetoresistive sensor is as shown in FIG. 18B, and the Tr <Tw(+d1)|P(+d2)<Tw(-d1)|P(+d2)<Tb<Tw(+d2)|P(+d2)<Tw(-d2)|P(+d2)<Tdである。

[0074] Method II: As shown in FIG. 19A, the laser spot 8 scans the +d2 push magnetoresistive sensing unit array 13 along the direction 9, the magnetic field generator generates a direction +d2 magnetic field 6(2), and only the +d2 push magnetoresistive sensing unit array 13 is written in the direction +d2 magnetic field 13(2), the magnetic moment of the adjacent -d1 pull magnetoresistive sensing unit array 12 is not affected, and the magnetic moment of the adjacent -d2 pull magnetoresistive sensing unit array 14 is affected, and the temperature profile is as shown in FIG. 19B, and Tr <Tw(-d1)|P(+d2)<Tb<Tw(+d2)|P(+d2)<Tw(-d2)|P(+d2)<Tdである。

[0075] Optionally, 4) writing the magnetic moment direction -d2 of the antiferromagnetic layer to the -d2 pull magnetoresistive sensing unit array includes the following two methods:

[0076] Method I: As shown in FIG. 20A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, as well as the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14 along the direction 9, and the magnetic field generator (not marked here) generates a magnetic field 6 in the direction -d2 (3), and only the -d2 pull magnetoresistive sensing unit array 14 is written in the direction -d2 magnetic field 13 (3), and the temperature profile is as shown in FIG. 20B. <Tw(+d1)|P(-d2)<Tw(-d1)|P(-d2)<Tw(+d2)|P(-d2)<Tb<Tw(-d2)|P(-d2)<Tdである。

[0077] Method II: As shown in FIG. 21A, the laser spot 8 scans along the −d2 pull magnetoresistive sensing unit array 14 along the direction 9, and the two magnetic field generators generate a magnetic field 6 (3) in the direction −d2, and a magnetic moment 13 (3) in the direction −d2 is written only in the −d2 pull magnetoresistive sensing unit array 14, and the magnetic moment of the adjacent +d2 push magnetoresistive sensing unit array 13 is affected, and the temperature profile is as shown in FIG. 21B. <Tw(+d2)|P(-d2)<Tb<Tw(-d2)|P(-d2)<Tdである。

[0078] As an example, writing the magnetic moment directions +d and -d of the antiferromagnetic layer of a three-axis push-pull magnetoresistive sensor may include six steps, namely: 1) writing the magnetic moment direction +d1 of the antiferromagnetic layer to the +d1 push magnetoresistive sensing unit array; 2) writing the magnetic moment direction -d1 of the antiferromagnetic layer to the -d1 pull magnetoresistive sensing unit array; 3) writing the magnetic moment direction +d2 of the antiferromagnetic layer to the +d2 push magnetoresistive sensing unit array; 4) writing the magnetic moment direction -d2 of the antiferromagnetic layer to the -d2 pull magnetoresistive sensing unit array; 5) writing the magnetic moment direction +d3 of the antiferromagnetic layer to the +d3 push magnetoresistive sensing unit array; and 6) writing the magnetic moment direction -d3 of the antiferromagnetic layer to the -d3 pull magnetoresistive sensing unit array.

[0079] Optionally, 1) writing the magnetic moment direction +d1 of the antiferromagnetic layer to the +d1 push magnetoresistive sensing unit array includes the following three methods:

[0080] Method I: As shown in FIG. 22A, a magnetic field annealing furnace 7 is used, and its magnetic field generator 5(1) is used to generate a direction +d1 magnetic field 6, and the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 located on the substrate 3 all obtain a direction +d1 magnetic moment 13(0), and the +d1 push thermal control layer 41 and the -d1 pull thermal control layer 42, the +d2 push thermal control layer 43 and the -d2 thermal control layer 44, and the +d3 push thermal control layer 45 and the -d3 thermal control layer 46 do not function, and the temperature profile is as shown in FIG. 22B, and Tb <Tw(+d1)|P(oven)=Tw(-d1)|P(oven)=Tw(+d2)|P(oven)=Tw(-d2)|P(oven)=Tw(+d3)|P(oven)=Tw(-d3)|P(oven)<Tdである。

[0081] Method II: As shown in FIG. 23A, the laser spot 8 scans along direction 9 over the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16. The magnetic field generating device 5(1) generates a +d1 direction magnetic field 6. The +d1 direction magnetic moment 13(0) is written into all the magnetoresistive sensing units. Its temperature profile is as shown in FIG. 23B, where Tb < Tw(+d1)|P(+d1) < Tw(-d1)|P(+d1) < Tw(+d2)|P(+d1) < Tw(-d2)|P(+d1) < Tw(+d3)|P(+d1) < Tw(-d3)|P(+d1) < Td. That is, due to the action of the same laser output P(+d1), the temperature rises Tw(+d1)|P(+d1) of the +d1 push magnetoresistive sensing units, Tw(-d1)|P(+d1) of the -d1 pull magnetoresistive sensing units, Tw(+d2)|P(+d1) of the +d2 push magnetoresistive sensing units, Tw(-d2)|P(+d1) of the -d2 pull magnetoresistive sensing units, Tw(+d3)|P(+d1) of the +d3 push magnetoresistive sensing units, and Tw(-d3)|P(+d1) of the -d3 pull magnetoresistive sensing units are arranged in ascending order.

[0082] Method III: As shown in FIG. 24A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 along direction 9. The magnetic field generating device 5(1) generates a +d1 direction magnetic field 6. The +d1 push magnetoresistive sensing unit array 11 is written with the +d1 direction magnetic moment 13(0). As shown in FIG. 24B, the +d1 push magnetoresistive sensing unit array 11 has a temperature Tw(+d1)|P(+d1), and the adjacent -d1 pull magnetoresistive sensing unit array 12 has a temperature Tw(-d1)|P(+d1), which may result in writing the magnetic moment into other magnetoresistive sensing units.

[0083] Optionally, 2) writing the magnetic moment direction -d1 of the antiferromagnetic layer to the -d1 pull magnetoresistive sensing unit array includes the following two methods:

[0084] Method I: As shown in FIG. 25A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 along the direction 9, and the magnetic field generator 5 (1) generates a magnetic field 6 (1) in the direction -d1, so that only the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13, the -d2 pull magnetoresistive sensing unit array 14, the +d3 push magnetoresistive sensing unit array 15, and the -d3 pull magnetoresistive sensing unit array 16 are all written in the direction -d1 magnetic field 13 (1), and the temperature profile thereof is as shown in FIG. 25B. <Tw(+d1)|P(-d1)<Tb<Tw(-d1)|P(-d1)<Tw(+d2)|P(-d1)<Tw(-d2)|P(-d1)<Tw(+d3)|P(-d1)<Tw(-d3)|P(-d1)<Tdである。

[0085] Method II: As shown in FIG. 26A, the laser spot 8 scans the -d1 pull magnetoresistive sensing unit array 12 along the direction 9, the magnetic field generator 5 (1) generates a magnetic field 6 (1) in the direction -d1, and only the -d1 pull magnetoresistive sensing unit array 12 is written in the direction -d1 magnetic field 13 (1), the magnetic moment of the adjacent +d1 push magnetoresistive sensing unit array 11 is not affected, and the magnetic moment of the adjacent +d2 push magnetoresistive sensing unit array 13 is affected, and the temperature profile is as shown in FIG. 26B, and Tr <Tw(+d1)|P(-d1)<Tb<Tw(-d1)|P(-d1)<Tw(+d2)|P(-d1)<Tdである。

[0086] Optionally, 3) writing the magnetic moment direction +d2 of the antiferromagnetic layer to the +d2 push magnetoresistive sensing unit array includes the following two methods:

[0087] Method I: As shown in FIG. 27A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 along the direction 9, and the magnetic field generator (not marked here) generates a direction +d2 magnetic field 6(2), and only the +d2 push magnetoresistive sensing unit array 13, the -d2 pull magnetoresistive sensing unit array 14, the +d3 push magnetoresistive sensing unit array 15, and the -d3 pull magnetoresistive sensing unit array 16 are written in the direction +d2 magnetic field 13(2), and the temperature profile is as shown in FIG. 27B, and Tr <Tw(+d1)|P(+d2)<Tw(-d1)|P(+d2)<Tb<Tw(+d2)|P(+d2)<Tw(-d2)|P(+d2)<Tw(+d3)|P(+d2)<Tw(-d3)|P(+d2)<Tdである。

[0088] Method II: As shown in FIG. 28A, the laser spot 8 scans the +d2 push magnetoresistive sensing unit array 13 along the direction 9, the magnetic field generator generates a direction +d2 magnetic field 6(2), and the direction +d2 magnetic field 13(2) is written only to the +d2 push magnetoresistive sensing unit array 13, the magnetic moment of the adjacent -d1 pull magnetoresistive sensing unit array 12 is not affected, and the magnetic moment of the adjacent -d2 pull magnetoresistive sensing unit array 14 is affected, and the temperature profile is as shown in FIG. 28B, and Tr <Tw(-d1)|P(+d2)<Tb<Tw(+d2)|P(+d2)<Tw(-d2)|P(+d2)<Tdである。

[0089] Optionally, 4) writing the magnetic moment direction -d2 of the antiferromagnetic layer to the -d2 pull magnetoresistive sensing unit array includes the following two methods:

[0090] Method I: As shown in FIG. 29A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 along the direction 9, and the magnetic field generator (not marked here) generates a magnetic field 6 in the direction -d2 (3), and only the -d2 pull magnetoresistive sensing unit array 14, the +d3 push magnetoresistive sensing unit array 15, and the -d3 pull magnetoresistive sensing unit array 16 are written in the direction -d2 magnetic field 13 (3), and the temperature profile is as shown in FIG. 29B, and Tr <Tw(+d1)|P(-d2)<Tw(-d1)|P(-d2)<Tw(+d2)|P(-d2)<Tb<Tw(-d2)|P(-d2)<Tw(+d3)|P(-d2)<Tw(-d3)|P(-d2)<Tdである。

[0091] Method II: As shown in FIG. 30A, the laser spot 8 scans the -d2 pull magnetoresistive sensing unit array 14 along the direction 9, the magnetic field generator generates a magnetic field 6(3) in the direction -d2, and a magnetic moment 13(3) in the direction -d2 is written only to the -d2 pull magnetoresistive sensing unit array 14, the magnetic moment of the adjacent +d2 push magnetoresistive sensing unit array 13 is not affected, and the magnetic moment of the adjacent +d3 push magnetoresistive sensing unit array 15 is affected, and the temperature profile is as shown in FIG. 30B. <Tw(+d2)|P(-d2)<Tb<Tw(-d2)|P(-d2)<Td<Tw(+d3)|P(-d2)<Tdである。

[0092] Optionally, 5) writing the magnetic moment direction +d3 of the antiferromagnetic layer in the +d3 push magnetoresistive sensing unit array includes the following two methods: Method I: As shown in FIG. 31A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 along the direction 9, the magnetic field generator 5 (5) generates a magnetic field 6 (4) in the direction +d3, and the magnetic moment 13 (4) in the direction +d3 is written only to the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16, and the temperature profile is as shown in FIG. 31B. <Tw(+d1)|P(+d3)<Tw(-d1)|P(+d3)<Tw(+d2)|P(+d3)<Tw(-d2)|P(+d3)<Tb<Tw(+d3)|P(+d3)<Tw(-d3)|P(+d3)<Tdである。

[0093] Method II: As shown in FIG. 32A, the laser spot 8 scans the +d3 push magnetoresistive sensing unit array 15 along the direction 9, the magnetic field generator 5 (5) generates a magnetic field 6 (4) in the direction +d3, and a magnetic field 13 (4) in the direction +d3 is written only to the +d3 push magnetoresistive sensing unit array 15, the magnetic moment of the adjacent -d2 pull magnetoresistive sensing unit array 14 is not affected, and the magnetic moment of the adjacent -d3 pull magnetoresistive sensing unit array 16 is affected, and the temperature profile is as shown in FIG. 32B, and Tr <Tw(-d2)|P(+d3)<Td<Tw(+d3)|P(+d3)<Tw(-d3)|P(+d3)<Tdである。

[0094] Optionally, 6) writing the magnetic moment direction -d3 of the antiferromagnetic layer to the -d3 pull magnetoresistive sensing unit array includes the following two methods:

[0095] Method I: As shown in FIG. 33A, the laser spot 8 scans the +d1 push magnetoresistive sensing unit array 11 and the -d1 pull magnetoresistive sensing unit array 12, the +d2 push magnetoresistive sensing unit array 13 and the -d2 pull magnetoresistive sensing unit array 14, and the +d3 push magnetoresistive sensing unit array 15 and the -d3 pull magnetoresistive sensing unit array 16 along the direction 9, and the magnetic field generator 5 (5) generates a magnetic field 6 (5) in the direction -d3, and a magnetic moment 13 (5) in the direction -d3 is written only to the -d3 pull magnetoresistive sensing unit array 16, and the temperature profile is as shown in FIG. 33B. <Tw(+d1)|P(-d3)<Tw(-d1)|P(-d3)<Tw(+d2)|P(-d3)<Tw(-d2)|P(-d3)<Tw(+d3)|P(-d3)<Tb<Tw(-d3)|P(-d3)<Tdである。

[0096] Method II: As shown in FIG. 34A, the laser spot 8 scans the −d3 pull magnetoresistive sensing unit array 16 along the direction 9, the magnetic field generator 5 (5) generates a magnetic field 6 (5) in the direction −d3, and a magnetic moment 13 (5) in the direction −d3 is written only to the −d3 pull magnetoresistive sensing unit array 16, and the magnetic moment of the adjacent +d3 push magnetoresistive sensing unit array 15 is not affected, and the temperature profile is as shown in FIG. 34B. <Tw(+d3)|P(-d3)<Td<Tw(-d3)|P(-d3)<Tdである。

[0097] It should be noted that the above is merely the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiment in the specification, and those skilled in the art can make various obvious changes, rearrangements, combinations, and substitutions without departing from the scope of the present invention. Thus, although the present invention has been described in more detail by the above embodiment, the present invention is not limited thereto, and can include many other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A laser writable apparatus for programming a magnetoresistive device, comprising a substrate, a magnetoresistive sensor and a thermal control layer, arranged in a stack, with a non-magnetic insulating layer between the magnetoresistive sensor and the thermal control layer for electrical isolation, the magnetoresistive sensor being comprised of a magnetoresistive sensing unit which is a multi-layer thin film stack structure with an antiferromagnetic layer; The laser-writable device is configured such that, during a laser writing stage for programming, the thermal control layer and / or film layer parameters of the magnetoresistive sensor are changed to adjust the rate of change of temperature of the magnetoresistive sensor with laser power, and the magnetic moment of the antiferromagnetic layer in the magnetoresistive sensor is programmed by increasing or decreasing the temperature written to the magnetoresistive sensor with the same laser power, and the film layer parameters include at least one of a film layer material and a film layer thickness.

2. 2. The laser-writable device of claim 1, wherein the magnetoresistive sensor is a giant magnetoresistive (GMR) sensor, a tunneling magnetoresistive (TMR) sensor, or an anisotropic magnetoresistive (AMR) sensor.

3. In a direction from the substrate to the thermal control layer, the multi-layer thin film stack structure comprises, sequentially arranged in a stack, a seed layer, the antiferromagnetic layer, a free layer, a top electrode layer, and a cap layer, a first insulating layer being disposed between the substrate and the seed layer; the laser writable device is configured to change the material of at least one of the film layers of the thermal control layer, the first insulating layer, the seed layer, the top electrode layer, and the cap layer to increase or decrease the temperature at which the magnetoresistive sensor is written with the same laser power; and / or 2. The laser writable device of claim 1, wherein the laser writable device is configured to vary a thickness of at least one of the film layers of the thermal control layer, the first insulating layer, the seed layer, the top electrode layer, and the cap layer to increase or decrease the temperature at which the magnetoresistive sensor is written with the same laser power.

4. 2. The laser-writable device of claim 1, wherein the magnetoresistive sensor is a push-pull magnetoresistive sensor, the push-pull magnetoresistive sensor being composed of a push magnetoresistive sensing unit array and a pull magnetoresistive sensing unit array, and both the push magnetoresistive sensing unit array and the pull magnetoresistive sensing unit array are composed of magnetoresistive sensing units.

5. 5. The laser-writable device of claim 4, wherein the push-pull magnetoresistive sensor is a full-bridge structure, a half-bridge structure, or a quasi-bridge structure.

6. 5. The laser-writable device of claim 4, wherein the push-pull magnetoresistive sensor is a single-axis push-pull magnetoresistive sensor, a dual-axis push-pull magnetoresistive sensor, or a triple-axis push-pull magnetoresistive sensor.

7. 2. The laser writable apparatus of claim 1, wherein the thermal control layer comprises a non-magnetic low laser absorption coefficient material or a high laser absorption coefficient material, the low laser absorption coefficient material comprising at least one of tantalum, titanium, copper, molybdenum, gold, silver, aluminum, platinum, and tin, and the high laser absorption coefficient material comprising at least one of zirconium oxide, titanium oxide, carbon film, phosphate, and aluminum titanium nitride.

8. 10. The laser-writable apparatus of claim 1, wherein the material of the thermal control layer comprises carbon black, a non-magnetic laser absorbing resin, or a non-magnetic laser absorbing coating.

9. 10. The laser writable apparatus of claim 1, wherein the laser has a wavelength in the range of 100 nm to 3000 nm.

10. 10. A laser writing method for programming a magnetoresistive device implemented by a laser writing system for programming, the laser writing system for programming comprising a magnetic field generating device and a laser writable device according to any one of claims 1 to 9, The laser writing method for programming of the laser writing system for programming comprises: Varying film layer parameters of the thermal control layer and / or the magnetoresistive sensor, including at least one of a film layer material and a film layer thickness, during a laser writing step for programming; and adjusting the rate of change of temperature of the magnetoresistive sensor with laser power to write higher or lower temperatures to the magnetoresistive sensor with the same laser power.

11. The magnetoresistive sensor is a push-pull magnetoresistive sensor, the push-pull magnetoresistive sensor comprising a push magnetoresistive sensing unit array and a pull magnetoresistive sensing unit array, the antiferromagnetic layer of the push magnetoresistive sensing unit array has a magnetic moment direction +di, the antiferromagnetic layer of the pull magnetoresistive sensing unit array has a magnetic moment direction -di, i is a positive integer, 1≦i≦3; 11. The laser writing method for programming of claim 10, further comprising: writing a magnetic moment into the antiferromagnetic layer of the push-pull magnetoresistive sensor, the magnetic moment direction including: writing the magnetic moment direction +di of the antiferromagnetic layer into the push magnetoresistive sensing unit array; and writing the magnetic moment direction −di of the antiferromagnetic layer into the pull magnetoresistive sensing unit array.

12. Writing the magnetic moment direction +di of the antiferromagnetic layer to the push magnetoresistive sensing unit array comprises: performing a magnetic field thermal annealing in a direction +di on the wafer by setting a magnetic field annealing power to P and a temperature to T, such that the antiferromagnetic layer of each of the magnetoresistive sensing unit arrays has the magnetic moment direction +di; or 12. The laser writing method for programming of claim 11, comprising: setting the laser power to P(+di) and the temperature to Tdi, and generating a magnetic field in a direction +di to write the magnetic moment in the direction +di into the antiferromagnetic layer of the push magnetoresistive sensing unit array.

13. Writing the magnetic moment direction −d i of the antiferromagnetic layer to the pull magnetoresistive sense unit array includes: setting the magnetic field annealing power to P and the temperature to T, and performing a direction -di magnetic field thermal annealing on the wafer, such that the antiferromagnetic layer of each of the magnetoresistive sensing unit arrays has the magnetic moment direction -di; or 13. The laser writing method for programming of claim 12, comprising: setting the laser power at P(-di) and the temperature at Tdi, and generating a directional -di magnetic field to write the directional -di magnetic moment into the antiferromagnetic layer of the pull magnetoresistive sense unit array.

14. The laser writing method for programming according to claim 13, wherein Td1<Td2<Td3.

15. 15. The laser writing method for programming of claim 14, wherein Tb<Td1<Td2<Td3<Td, the Tb being a write temperature of the magnetoresistive sensing unit array, and the Td being a damage temperature of the magnetoresistive sensing unit array.

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