CN-116106800-B - Single-chip triaxial magnetic field sensor and preparation method thereof

CN116106800BCN 116106800 BCN116106800 BCN 116106800BCN-116106800-B

Abstract

The invention discloses a single-chip triaxial magnetic field sensor and a preparation method thereof, wherein a magnetically sensitive film is grown on a substrate, a magnetically sensitive film array structure is formed through a photoetching process, an insulating protection layer and a seed layer in front of an electroplating magnetic flux collector are prepared above the film array, the electroplating magnetic flux collector layer is arranged on the seed layer, and corresponding magnetic flux controller layers are sequentially arranged from thin to thick, namely film growth and etching are only needed on a wafer/substrate from beginning to end, and the improvement of yield is facilitated due to the film process which is completely the same as that of the wafer, and the process complexity is greatly reduced. Compared with a method for independently measuring the magnetic field of each axis, the method avoids the interference of the magnetic field in the non-sensitive axis direction on the chip measurement, has simple formula, and is convenient to acquire more accurate detection data by adopting a data fusion method such as machine learning and the like.

Inventors

ZHOU KE
JIN QINGREN
LU BAIHUA
MO ZHIYUE
LIU PENG
QIN LIWEN
YAO ZHIYANG

Assignees

广西电网有限责任公司电力科学研究院

Dates

Publication Date: 20260505
Application Date: 20230105

Claims (10)

1. A single chip tri-axial magnetic field sensor, comprising: A substrate for providing support for other devices; The magnetic sensitive thin film arrays are arranged above the substrate, have sensitive characteristics to magnetic fields in a single in-plane direction, and are covered with insulating protective layers; each group of the magneto-sensitive film arrays are connected with the corresponding fixed value resistor module to form a Wheatstone bridge structure; And each group of the magnetic sensitive film arrays is connected with corresponding magnetic flux controllers with different thicknesses, and the magnetic flux controllers are arranged above the magnetic sensitive film arrays.
2. The single chip tri-axial magnetic field sensor of claim 1 wherein said magnetically sensitive thin film array includes a plurality of equally sized magnetically sensitive structural elements, all having sensitive characteristics to a single in-plane directional magnetic field.
3. The single chip triaxial magnetic field sensor according to claim 2, wherein the magnetically sensitive structure unit is a tunneling magneto-resistive thin film device or a giant magneto-resistive thin film device or an anisotropic magneto-resistive thin film device, and an array is formed by series-parallel connection, and a sensitive axis direction of the array is perpendicular to a long axis direction of the magnetically sensitive structure unit.
4. The single chip tri-axial magnetic field sensor of claim 1 wherein said fixed value resistive module is in the same horizontal plane as the array of magnetically sensitive films.
5. The single chip tri-axial magnetic field sensor of claim 1, wherein the long end of the magnetically sensitive thin film array has a fixed angle of 10 ° to 80 ° with the long end of the magnetic flux controller.
6. The single chip tri-axial magnetic field sensor of claim 1, wherein the magnetic flux controller is a material having a high magnetic permeability.
7. The single-chip triaxial magnetic field sensor according to claim 1, wherein each group of magnetically sensitive thin film arrays are connected in series and parallel with a fixed value resistor module to form a wheatstone bridge structure, voltage input ends of each wheatstone bridge structure are connected in parallel, and output ends of each wheatstone bridge structure are independent.
8. The single chip tri-axial magnetic field sensor of claim 7, wherein each measures an output voltage signal U1, U2, U3 of the wheatstone bridge configuration, respectively, and Un, expressed as Un = Nnx x Hx + Nny x Hy + Nnz x Hz, wherein Nnx, nny, nnz are sensitivity coefficients of the sensitive unit to tri-axial magnetic fields Hx, hy, hz, respectively.
9. The single-chip triaxial magnetic field sensor according to claim 1, characterized in that each group of magnetically sensitive thin film arrays has different measurement sensitivity and measurement range for triaxial magnetic fields, and each group of magnetically sensitive thin film arrays can be used as a single-axis sensor to respectively realize measurement for magnetic fields in different measurement range.
10. The preparation method of the single-chip triaxial magnetic field sensor is characterized by comprising the following steps of: Growing a magnetically sensitive film on a substrate; preparing a magnetically sensitive film array structure and a wire through a photoetching process; preparing an insulating protective layer and a seed layer in front of the electroplating flux collector over the thin film array; A flux concentrator layer is electroplated over the seed layer, completing the corresponding flux controller layers in sequence from thin to thick.

Description

Single-chip triaxial magnetic field sensor and preparation method thereof Technical Field The invention belongs to the technical field of magnetic sensors, and particularly relates to a single-chip triaxial magnetic field sensor and a preparation method thereof. Background The miniaturized integrated triaxial magnetic field sensor can accurately feed back magnetic field signals in a three-dimensional space, is expected to further improve measurement accuracy and precision of a magnetic sensor, simultaneously realizes functions of scanning the space magnetic field signals and the like, and is widely applied to various fields of power grids, energy management, new energy automobiles, industrial manufacturing and the like. Currently, manufacturers at home and abroad including Jiangsu multidimensional and Japanese TDK respectively promote three-axis magnetic field sensors. However, due to the limitation of process conditions, the existing triaxial magnetic field sensor needs the splicing combination of a plurality of uniaxial magnetic sensitive chips with different sensitive axes, so that three different magnetic sensitive films are respectively grown on at least 2-3 wafers, etching is respectively carried out, and then splicing is carried out, thereby improving the cost and the risk of film uniformity and yield. Disclosure of Invention Aiming at the current situation that a plurality of TMR chips are needed to be spliced for the traditional triaxial magnetic field sensor in the prior art, the process complexity is high, the cost and the yield are to be upgraded, the invention provides the single-chip triaxial magnetic field sensor realized by the same film single etching process based on single wafer growth. According to one aspect of the embodiments of the present invention, there is provided a single-chip tri-axial magnetic field sensor, including: A substrate for providing support for other devices; The magnetic sensitive thin film arrays are arranged above the substrate, have sensitive characteristics to magnetic fields in a single in-plane direction, and are covered with insulating protective layers; each group of the magneto-sensitive film arrays are connected with the corresponding fixed value resistor module to form a Wheatstone bridge structure; And each group of the magnetic sensitive film arrays is connected with corresponding magnetic flux controllers with different thicknesses, and the magnetic flux controllers are arranged above the magnetic sensitive film arrays. Optionally, the magnetically sensitive thin film array includes a plurality of magnetically sensitive structural units with the same size, and all the magnetically sensitive structural units have sensitivity characteristics to a magnetic field in a single in-plane direction. Optionally, the magnetically sensitive structure unit is a tunneling magneto-resistance film device, a giant magneto-resistance film device or an anisotropic magneto-resistance film device, and an array is formed by serial-parallel connection, and the sensitive axis direction of the array is perpendicular to the long axis direction of the magnetically sensitive structure unit. Optionally, the fixed value resistor module and the magnetically sensitive thin film array are located on the same horizontal plane. Optionally, a fixed included angle of 10-80 degrees exists between the long end of the magnetically sensitive thin film array and the long end of the magnetic flux controller. Optionally, the magnetic flux controller is a material with high magnetic permeability. Optionally, each group of magnetically sensitive film arrays are connected in series and parallel with the fixed-value resistor module to form a Wheatstone bridge structure, voltage input ends of each Wheatstone bridge structure are connected in parallel, and output ends of each Wheatstone bridge structure are independent. Alternatively, the output voltage signals U1, U2, U3 of the wheatstone bridge configuration are measured separately, un, expressed as un= Nnx ×hx+ Nny ×hy+ Nnz ×hz, wherein Nnx, nny, nnz are the sensitivity coefficients of the sensitive unit to the triaxial magnetic fields Hx, hy, hz, respectively. Optionally, the measurement sensitivity and measurement range of each group of the magnetically sensitive film arrays to the triaxial magnetic field are different, and each group of the magnetically sensitive film arrays can be used as a single-axis sensor to respectively realize the measurement of the magnetic field in different measurement range. According to another aspect of the embodiment of the present invention, there is also provided a method for manufacturing a single-chip triaxial magnetic field sensor, including: Growing a magnetically sensitive film on a substrate; preparing a magnetically sensitive film array structure and a wire through a photoetching process; preparing an insulating protective layer and a seed layer in front of the electroplating flux collector over the thin f