CN-115950735-B - Flexible magnetic sensor array capable of stretching in all directions and preparation method thereof

CN115950735BCN 115950735 BCN115950735 BCN 115950735BCN-115950735-B

Abstract

The invention provides a flexible magnetic sensor array capable of stretching in all directions and a preparation method thereof, wherein the flexible magnetic sensor array comprises a high-elasticity substrate film layer, an array rigid island layer and a magnetic sensor layer, the array rigid island layer comprises a plurality of rigid islands which are arranged on the high-elasticity substrate film layer and are arranged in an array, the magnetic sensor layer comprises a magnetic sensor arranged on each rigid island, each rigid island is respectively led out of the magnetic sensor with a plurality of elastic electrodes, all the elastic electrodes are attached to the high-elasticity substrate film layer and led out to the edge of the high-elasticity substrate film layer, the Young modulus of the magnetic sensor is larger than that of the rigid island, and the Young modulus of the rigid island is larger than that of the high-elasticity substrate film layer. The high-elasticity substrate film layer, the array rigid island layer and the magnetic sensor layer are in a modulus gradient structure, and have a strain isolation effect under deformation, so that the high-elasticity substrate film layer bears most of strain, and the original performance of the magnetic sensor is ensured.

Inventors

LI RUNWEI
PAN LILI
XIE YALI
YANG HUALI
Hu Haixu
LI XINZE

Assignees

中国科学院宁波材料技术与工程研究所

Dates

Publication Date: 20260508
Application Date: 20221128

Claims (8)

1. The flexible magnetic sensor array capable of stretching in all directions is characterized by comprising a high-elasticity substrate film layer (1), an array rigid island layer and a magnetic sensor layer, wherein the array rigid island layer comprises a plurality of rigid islands (2) which are arranged on the high-elasticity substrate film layer (1) and are arranged in an array mode, the magnetic sensor layer comprises a magnetic sensor (3) which is arranged on each rigid island (2), a plurality of elastic electrodes (4) are respectively led out of the magnetic sensor (3) by each rigid island (2), all the elastic electrodes (4) are attached to the high-elasticity substrate film layer (1) and led out to the edge of the high-elasticity substrate film layer (1), the Young modulus of the magnetic sensor (3) is larger than that of the rigid islands (2), and the Young modulus of the rigid islands (2) is larger than that of the high-elasticity substrate film layer (1); the high-elasticity substrate film layer (1) is made of PDMS, PU or Ecofelx, the rigid island (2) is made of polyimide or photoresist, and the elastic electrode (4) is made of liquid metal or silver nanowire; the surface roughness of the high-elasticity substrate film layer (1) and the rigid island (2) is less than 1 nanometer.
2. A flexible magnetic sensor array stretchable in all directions according to claim 1, characterized in that the rigid islands (2) and the magnetic sensors (3) are circular or polygonal.
3. A method for preparing a flexible magnetic sensor array capable of being stretched in each direction according to any one of claims 1 to 2, comprising a forward manufacturing method and a reverse manufacturing method, wherein the forward manufacturing method sequentially comprises steps S1, S2, S3, S4 and S5, and the reverse manufacturing method sequentially comprises steps S1, S4, S3, S2 and S5, and wherein S1, providing a temporary substrate layer and cleaning; S2, manufacturing a high-elasticity substrate film layer (1), namely uniformly mixing a precursor of the high-elasticity substrate with a curing agent according to a preset weight ratio, spin-coating the mixture on the upper layer, and drying and curing the mixture to obtain the high-elasticity substrate film layer (1); S3, manufacturing an array rigid island layer, namely spin-coating photoresist on the upper layer, carrying out photoetching by using a photoetching plate with a specific pattern after baking and curing to obtain the array rigid island layer, and then sequentially carrying out development, fixation, baking and curing to obtain a plurality of rigid islands (2); S4, manufacturing a magnetic sensor layer, namely manufacturing a plurality of magnetic films with spin valve structures on the upper layer through magnetron sputtering growth to obtain the magnetic sensor layer; S5, each rigid island (2) in the array rigid island layer is led out of a plurality of elastic electrodes (4) from the corresponding magnetic sensor (3), and the led-out elastic electrodes (4) are attached to the high-elasticity substrate film layer (1).
4. A method for preparing a flexible magnetic sensor array capable of being stretched in all directions according to claim 3, wherein in the forward manufacturing method and the reverse manufacturing method, the step S1 comprises the following steps: S11, providing a silicon wafer as a temporary substrate layer, and cleaning the surface of the silicon wafer by using plasma; s12, spin-coating a dextran solution with a specific concentration on the surface of the cleaned silicon wafer, and baking to obtain the sacrificial layer.
5. A method of manufacturing a flexible magnetic sensor array according to claim 3 or 4, wherein in the forward direction manufacturing method, a cleaning step is further provided after step S2 and before step S3, wherein the surface of the high elastic substrate film layer (1) is cleaned by using plasma.
6. A method for fabricating a flexible magnetic sensor array capable of being stretched in all directions as defined in claim 4, wherein in the forward fabricating method and the reverse fabricating method, spin-coating the photoresist is performed in step S3, and then idle for a certain period of time at a specific rotational speed.
7. A method for preparing a flexible magnetic sensor array capable of stretching in all directions according to claim 4, wherein: In the forward manufacturing method, the step S4 comprises the steps of dissolving the sacrificial layer by using deionized water, removing the temporary substrate layer and drying by blow, fixing the sacrificial layer on the array rigid island layer by using a mask plate with a corresponding pattern, and manufacturing a magnetic film with a spin valve structure on each rigid island (2) by magnetron sputtering growth to obtain a magnetic sensor layer; in the reverse manufacturing method, the step S4 comprises the steps of manufacturing a plurality of magnetic films with spin valve structures on the sacrificial layer through magnetron sputtering growth to obtain a magnetic sensor layer, and a stripping step of dissolving the sacrificial layer by deionized water, removing the temporary substrate layer and drying before the step S5 after the step S2.
8. A method of manufacturing a flexible magnetic sensor array according to claim 3, wherein in the reverse manufacturing method, the step S1 comprises providing a mica sheet as a temporary substrate layer, cleaning the mica sheet with plasma, and peeling the mica sheet layer by layer using an adhesive tape after the step S2 and before the step S5.

Description

Flexible magnetic sensor array capable of stretching in all directions and preparation method thereof Technical Field The invention relates to the technical field of flexible magnetic sensors, in particular to a flexible magnetic sensor array capable of being stretched in all directions and a preparation method thereof. Background With the rapid development of the internet of things and wearable devices, flexible electronic technology is attracting attention. The flexible electronic material and the device can be applied to various complex surfaces including human skin by virtue of the characteristics of being telescopic, biocompatible, not easy to damage, light, thin, small-sized and the like, so that the functional material can be remolded arbitrarily according to the requirements after being manufactured. Therefore, flexible electronics are widely used in flexible circuit boards, supercapacitors, biomedical, smart textile, and electronic skin, among other fields. The flexible magnetic sensor device can realize a series of unique functions including positioning navigation, stress detection, real-time monitoring, non-contact interaction and the like, and has become an important field in flexible electronic devices, and the core structure of the flexible magnetic sensor device is a magnetic film. Conventional magnetic films are fabricated on rigid silicon-based substrates, and the stretchability of such elements is difficult to exceed the inherent ductility of the material, far from meeting the stretchable magnetoelectronics capability requirements. To solve this problem, the most common method is to directly deposit a rigid multilayer film (with a curved pattern) on a flexible substrate by a direct deposition method, to obtain a flexible spin valve magnetic sensor, and to make it flexible to a certain extent. However, the magnetic film material is rigid, and is not matched with the modulus of the flexible substrate during stretching, so that defects are easily generated on the surface, and the stretchability and stability of the film cannot be effectively improved. Disclosure of Invention The invention aims to solve the technical problem of providing a flexible magnetic sensor array capable of stretching in all directions, and solving the problem of performance reduction caused by defects on the surface of a film when a magnetic sensor in the prior art is stretched. The flexible magnetic sensor array capable of stretching in all directions comprises a high-elasticity substrate film layer, an array rigid island layer and a magnetic sensor layer, wherein the array rigid island layer comprises a plurality of rigid islands which are arranged on the high-elasticity substrate film layer and are arranged in an array mode, the magnetic sensor layer comprises a magnetic sensor arranged on each rigid island, each rigid island is respectively provided with a plurality of elastic electrodes, all the elastic electrodes are attached to the high-elasticity substrate film layer and are led out to the edge of the high-elasticity substrate film layer, the Young modulus of the magnetic sensor is larger than that of the rigid island, and the Young modulus of the rigid island is larger than that of the high-elasticity substrate film layer. Compared with the prior art, the invention has the advantages that the arranged high-elasticity substrate film layer, the array rigid island layer and the magnetic sensor layer are in a modulus gradient structure, and can have strain isolation effect under deformation such as stretching, bending and torsion in all directions, so that the high-elasticity substrate film layer bears most strain, the magnetic sensor on the array rigid island layer keeps original performance, the service occasion and the service life of the magnetic sensor are greatly improved, and the array arrangement ensures that the sensitivity is higher. Preferably, the material of the high-elasticity substrate film layer is PDMS, PU or Ecofelx, the material of the rigid island is polyimide or photoresist, and the material of the elastic electrode is liquid metal or silver nanowire. The technical effects achieved by the technical scheme are that the high-elasticity substrate film layer is made of materials with low Young's modulus, so that most of strain can be born in deformation such as stretching, bending and twisting, the rigid island is made of materials with high Young's modulus, the magnetic sensor can keep original performance as transition, the elastic electrode is made of stretchable conductor materials with resistance which cannot change greatly under certain stretching, the wire cannot be broken under stretching, and the resistance cannot change greatly. Preferably, the surface roughness of the high-elasticity substrate film layer and the rigid island is less than 1 nanometer. The technical scheme has the advantages that the surface roughness is smaller, adhesion between layers can be facilitated, the stability o