Magnetic tunnel junction (MTJ) triaxial magnetic field sensor and packaging method thereof

Abstract

The invention discloses a magnetic tunnel junction (MTJ) triaxial magnetic field sensor, which comprises an X-axis bridge magnetic field sensor with the X axis as the sensitive direction, a Y-axis bridge magnetic field sensor with the Y axis as the sensitive direction, a Z-axis bridge magnetic field sensor with the Z axis as the sensitive direction and an application specific integrated circuit (ASIC) chip connected and matched with the X-axis bridge magnetic field sensor, the Y-axis bridge magnetic field sensor and the Z-axis bridge magnetic field sensor. The Z-axis magnetic field sensor comprises a substrate and an MTJ element prepared on the substrate, the Z-axis magnetic field sensor clings to and covers the ASIC chip to form a clinging side, an included angle is formed between the clinging side and the lateral side adjacent to the clinging side on the Z-axis magnetic field sensor, the included angle is an acute angle or an obtuse angle, and the X axis, the Y axis and the Z axis are intersected with each other in orthogonality mode. By means of the structure, the MTJ triaxial magnetic field sensor is high in integrated degree, higher in sensitivity, low in power consumption, better in linearity, wide in dynamic range, better in temperature characteristics and strong in anti-jamming capability.

Description

technical field [0001] The invention relates to the design of a magnetic field sensor, in particular to an MTJ three-axis magnetic field sensor and a packaging method thereof. Background technique [0002] Tunnel junction magnetoresistance sensor (MTJ, Magnetic Tunnel Junction) is a new type of magnetoresistance effect sensor that has been applied in industry in recent years. In the multilayer film material, as the magnitude and direction of the external magnetic field change, the resistance of the magnetic multilayer film changes significantly. It has a greater resistance change rate than the previously discovered and practically applied AMR (anisotropic magnetoresistance). At the same time, it has better temperature stability than Hall effect materials. The MTJ magnetic field sensor has the advantages of large resistance change rate, large output signal amplitude, high resistivity, low power consumption, and high temperature stability. Compared with AMR, GMR, and Hall de...

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Problems solved by technology

[0004]The MTJ elements deposited on the same silicon wafer usually have the same magnetic field strength required for their magnetic moment reversal, so the MTJ elements on the same silicon wafer, After annealing, the magnetization direction of the pinned layer is usually the same, which makes it very difficult to make a push-pull bridge sensor

The current mainstream GMR three-axis sensor is realized by packaging the X, Y, and Z-axis GMR magnetic field sensors of three chips together. It is large in size and high in packaging cost. Compared with the MTJ magnetic field sensor, it has the disadvantages of low sensitivity and high power consumption.

[0005] From the above methods, it can be seen that the existing three-axis magnetic field sensor using AMR, Hall, and GMR elements has the disadvantages of large volume, high power consumption, and low sensitivity. , and the MTJ three-axis magnetic field sensor is difficult to achieve in design

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