The preparation method of Magnetic Sensor and Magnetic Sensor
Technical field
The invention belongs to electronic communication technology field, relate to a kind of Magnetic Sensor, particularly relate to a kind of preparation method and Magnetic Sensor of Magnetic Sensor.
Background technology
Magnetic Sensor, according to its principle, can be divided into following a few class: Hall element, magnetodiode, anisotropic magnetoresistive element (AMR), tunnel junction magnetic resistance (TMR) element and giant magnetoresistance (GMR) element, induction coil, superconductive quantum interference magnetometer etc.
Electronic compass is one of important applied field of Magnetic Sensor, along with the fast development of consumer electronics in recent years, except navigation system, also have increasing smart mobile phone and panel computer also to start standard configuration electronic compass, bring very large application convenient to user.Magnetic Sensor of the prior art is planar magnetic transducer normally, can be used for magnetic field intensity on measurement plane and direction.
In recent years, the demand of Magnetic Sensor starts from two axially three axle development.Magnetic field intensity in plane and direction such as can represent by X and Y-axis both direction, then three-axis sensor also should be measured and plane orthogonal direction, X-Y axle place simultaneously, the magnetic field intensity namely in Z-direction and direction.To the Magnetic Sensor can measuring three axles simultaneously, be namely called magnetic sensor.
In magnetic sensor field, how exactly each sensing unit to be tested, especially to the test of Z axis sensitivity level, become the technical problem that this area is urgently to be resolved hurrily.
Summary of the invention
Technical problem to be solved by this invention is, provides a kind of Magnetic Sensor, can test, and provide its preparation method further to the magnetization body of reflection Z axis changes of magnetic field.
In order to solve the problem, the invention provides a kind of preparation method of Magnetic Sensor, comprise the steps: to provide substrate, described substrate surface has at least one boss; Z axis magnetic induction unit is formed at the sidewall of boss and the surface of substrate, and form sensing cell on the surface of substrate, described Z axis magnetic induction unit comprises the exit that a magnetization body and of fitting with boss sidewall extends to substrate surface, and described Z axis magnetic induction unit and sensing cell include magnetic material; Form continuous print electrode layer at described substrate surface, described electrode layer also covers described boss; Graphical described electrode layer, to form work electrode on sensing cell surface, and the magnetization body surface simultaneously on boss sidewall forms Autonomous test electrode.
Optionally, described substrate surface comprises multiple boss further, in the step of described graphical described electrode layer, forms the electrical connections connecting different boss surface detecting electrode separately further at substrate surface.
Optionally, before the step forming Z axis magnetic induction unit and sensing cell, the step of the Surface Creation insulating barrier of described substrate and boss is included in further.
Optionally, described magnetic material is selected from any one in anisotropic magnetoresistance material, giant magnetic resistance and tunnel magnetoresistive material.
Optionally, when forming magnetic material, substrate applies a magnetic field simultaneously, in order to induce the direction of magnetization of magnetic material.
Optionally, the angle of described magnetization body and substrate surface is between 45 ° to 90 °.
Optionally, before formation continuous print electrode layer step, comprise the steps: further to form dielectric layer on the surface of described Z axis magnetic induction unit and sensing cell; In the dielectric layer on sensing cell surface, form through hole, make the working electrode contact of sensing cell and follow-up formation.
Optionally, after formation Z axis magnetic induction unit and sensing cell magnetic material, substrate applies a magnetic field and anneals, in order to promote the magnetic property of magnetic material.
Optionally, interval one distance between sensing cell and exit, described distance is less than 5 microns.
Optionally, bonded to each other between sensing cell and exit.
Invention further provides a kind of Magnetic Sensor adopting said method to make, comprising: substrate; At least one boss of substrate surface; At the sensing cell on boss sidewall and the Z axis magnetic induction unit of substrate surface and the surface at substrate, described Z axis magnetic induction unit comprises the exit that a magnetization body and of fitting with boss sidewall extends to substrate surface, and described Z axis magnetic induction unit and sensing cell include magnetic material; Sensing cell surface has work electrode, and the magnetization body surface in groove has Autonomous test electrode further.
Optionally, described substrate surface comprises multiple boss further, comprises the electrical connections connecting different boss surface detecting electrode separately in boss surface further.
Optionally, comprise an insulating barrier on the surface of described substrate and boss, described Z axis magnetic induction unit and sensing cell are the surface being arranged at described insulating barrier further.
Optionally, described magnetic material is selected from any one in anisotropic magnetoresistance material, giant magnetic resistance and tunnel magnetoresistive material.
Optionally, described magnetic material has an induced magnetization direction of presetting.
Optionally, the angle of described magnetization body and substrate surface is between 45 ° to 90 °.
Optionally, the surface of described Z axis magnetic induction unit and sensing cell has dielectric layer, have above sensing cell through hole with working electrode contact.
Optionally, interval one distance between sensing cell and exit, described distance is less than 5 microns.
Optionally, bonded to each other between sensing cell and exit.
The invention has the advantages that, be provided with Autonomous test electrode on the surface of magnetization body, may be used for directly test magnetization body whether responsive to Z axis magnetic field.When passing through the electric current perpendicular to page in Autonomous test electrode, namely electrode can form the field signal (be namely the Z axis field signal of a simulation) parallel with sidewall in the side-walls of boss, this field signal body that can be magnetized exports sensing cell to, thus read because the resistance variations of this magnetic field generation, this change correspond to the induction in magnetic field.Because the magnetic field that Autonomous test electrode produces is corresponding with the intensity and direction applying electric current, Autonomous test and the rectification of Z axis transducer therefore just can be realized by this Autonomous test electrode.In the application of Magnetic Sensor, the Autonomous test of corresponding flat (X and Y-axis) direction Magnetic Sensor is relatively easy, and the Autonomous test of corresponding Z axis is more difficult.The invention provides a kind of to the self-monitoring function of Z axis Magnetic Sensor, and not additional process step, there is obvious competitiveness.And this Autonomous test electrode and work electrode are formed in same step simultaneously, therefore the complexity of manufacture craft is not increased, this Autonomous test electrode is also only be arranged on magnetization body surface, do not change shape and the position of magnetization body, therefore can not have influence on the intrinsic various characteristics of Magnetic Sensor yet.
Accompanying drawing explanation
It is the implementation step schematic diagram of the method for the invention embodiment shown in accompanying drawing 1.
It is the process schematic representation of the method for the invention embodiment shown in accompanying drawing 2A to accompanying drawing 7.
Embodiment
Below in conjunction with accompanying drawing, the preparation method of Magnetic Sensor provided by the invention and the embodiment of Magnetic Sensor are elaborated.
Be the implementation step schematic diagram of the method for the invention embodiment shown in accompanying drawing 1, comprise: step S10, provide substrate, described substrate surface has at least one boss; Step S11, at the Surface Creation insulating barrier of described substrate and boss; Step S12, Z axis magnetic induction unit is formed on the surface of boss sidewall and substrate, and form sensing cell on the surface of substrate, described Z axis magnetic induction unit comprises the exit that a magnetization body and of fitting with boss sidewall extends to substrate surface, and described Z axis magnetic induction unit and sensing cell include magnetic material; Step S13, form continuous print electrode layer at described substrate surface, described electrode layer also covers described boss; Step S14, graphical described electrode layer, to form work electrode on sensing cell surface, and the magnetization body surface simultaneously on boss sidewall forms Autonomous test electrode.
Shown in accompanying drawing 2A and 2B, refer step S10, provides substrate 20, and described substrate 20 surface has at least one boss 21.Accompanying drawing 2A is the front view of substrate 20, and accompanying drawing 2B is the profile of accompanying drawing 2A along AA direction.About the number of boss 21, this embodiment represents with three boss, and in other embodiment, certainly can also comprise more or less boss, its arrangement mode also can adjust as required.The cross sectional shape of described boss 21 can be rectangle or trapezoidal.
Shown in accompanying drawing 3, refer step S11, at the Surface Creation insulating barrier 32 of described substrate 20 and boss 21.This step is optional step, and the material for substrate 20 and boss 21 is electric conducting material, and the such as monocrystalline silicon of N-type or P type should implement this step to realize electric isolation; If substrate 20 and boss 21 itself have been insulating material, this step can have been omitted.Insulating barrier 32 also has the effect of inculating crystal layer, is conducive to the performance promoting subsequent deposition magnetic material.
Shown in accompanying drawing 4; refer step S12; Z axis magnetic induction unit 43 is formed on the surface of boss 21 sidewall and substrate 20; and form sensing cell 44 on the surface of substrate; described Z axis magnetic induction unit 43 comprises the exit 43b that a magnetization body 43a and fitted with boss 31 sidewall extends to substrate 20 surface; described Z axis magnetic induction unit 43 and sensing cell 44 include magnetic material, and the protective layer that can comprise magnetic material further to protect magnetic material in subsequent technique.Interval one distance between sensing cell 44 and exit 43b, between sensing cell 44 and exit 43b, the distance at interval is less than 5 microns, and sensing cell 44 and exit 43b can fit together.Can form one or more Z axis magnetic induction unit 43 on the surface of same boss 21, this embodiment only illustrates with one.In other embodiment, the number of Z axis magnetic induction unit 43 also can be multiple, and multiple Z axis magnetic induction unit 43 is arranged on the sidewall surfaces of the homonymy of boss 21.This step can adopt semiconductor technology to realize further; namely the continuous cover layer that continuous print comprises magnetic material and protective layer is first formed on the surface of substrate 20 and boss 21; adopt the technique such as photoetching and etching that continuous print cover layer is graphical again, form Z axis magnetic induction unit 43 and sensing cell 44.In above-mentioned steps, when forming magnetic material film, a magnetic field can be applied further on a substrate 20 simultaneously, in order to induce magnetic material to make it have the direction of magnetization preset, and making magnetic material have good performance.Above-mentioned step can also comprise the process of annealing after implementing: anneal in the magnetic field applying a fixed-direction on a substrate 20, improves the performance of magnetic material.
The direction of so-called Z axis refers to and plane orthogonal direction, substrate 20 place, and when Z axis has magnetic field, the direction of magnetization of magnetization body 43a changes, and the direction of magnetization of exit 43b is changed.Interval one distance between sensing cell 44 and exit 43b, when the direction of magnetization of exit 43b changes, the sensed direction of magnetization that also causes of sensing cell 44 changes, and the plane of the introduction by magnetic field of Z axis to substrate 20 place can be measured like this.With sensing cell 44, spacing distance between sensing cell 44 and exit 43b can sense that the changes of magnetic field of exit 43b is for standard.From above-mentioned test philosophy, magnetization body 43a is vertical with substrate 20 surface is conducive to the magnetic field of collecting Z-direction most, but this means that the sidewall of boss 21 is also vertical, and vertical sidewall is not easy to form cover layer on its surface.Therefore the sidewall of boss 21 can slightly be beneficial to form cover layer in inclination angle, the angular range on described magnetization body 43a and substrate 30 surface is advisable between 90 ° with 45 °.
Further, when the introduction by magnetic field of Z axis is measured to the plane at substrate 20 place, if also have magnetic field in-Y plane simultaneously, then sensing cell 44 simultaneously also likely in detection level face perpendicular to the magnetic field in sensing cell direction, during for detection Z-direction, the magnetic field of this horizontal direction is disturbed exactly.A kind of preferably by forming the magnetic sensor arrangement shown in four these embodiments and the method forming symmetrical electric bridge is offset in X-Y plane, so-called symmetrical electric bridge refers to that two brachium pontis of homonymy present same trend change along with the changes of magnetic field in X-Y plane, thus the voltage balancing out output is to the sensitiveness in the magnetic field in X-Y plane, thus what Z axis detecting unit was detected is pure Z axis signal.
Described magnetic material be selected from anisotropic magnetic resistance (AMR) material, giant magnetoresistance (GMR) material and tunnel magnetoresistive (TMR) material any one, can be such as NiFe material etc.
Protective layer material can be Ta, TaN or TiN material, its objective is protection flux material layer, makes it that change of magnetic property can not occur in the process of technique and application, also plays the object connecting flux material layer and subsequent electrode layer simultaneously.
Shown in accompanying drawing 5, refer step S13, form continuous print electrode layer 55 at described substrate surface, described electrode layer 55 also covers the surface into described boss 21.The technique forming electrode layer 55 can be such as depositing operation etc., and the material of electrode layer 55 is individual layer or multilayer material, such as, can be Al, AlCu, AlSi etc., or is the sandwich constructions such as Ti/TiN/AlCu/TiN/Ti, AlCu/TiN.
Before depositing electrode layers 55, can at the surface deposition dielectric layer (not shown) of Z axis magnetic induction unit 43 and sensing cell 44, in order to protect magnetic sensing element better, avoid that it is damaged in the process of technique, oxidation, impact.After metallization medium layer, also need to open corresponding through hole above sensing cell 44, thus realize the electric communication of test cell and electrode.
Shown in accompanying drawing 6, refer step S14, graphical described electrode layer 55, to form work electrode 66 on sensing cell 44 surface, and the magnetization body surface simultaneously on boss sidewall forms Autonomous test electrode 67.This step can adopt semiconductor planar technique to realize further, namely adopts the technique such as photoetching and etching that electrode layer 55 is graphical, forms work electrode 66.Work electrode 66 coordinates for same sensing cell 44, realize the detection after the plane of importing substrate 20 place, Z axis magnetic field, and Autonomous test electrode 67 may be used for for the magnetic field in magnetization body 43a applying Z-direction, whether responsive to Z axis magnetic field to test it, to complete the rectification to Z axis transducer.
Autonomous test electrode 67 is laid in the side of boss 21, be close on magnetization body 43a or dielectric layer, when passing through the electric current perpendicular to accompanying drawing 6 page in Autonomous test electrode 67, namely Autonomous test electrode 67 can form the field signal (be namely the Z axis field signal of a simulation) parallel with sidewall in the sidewall surfaces of boss 21, this field signal body 43a that can be magnetized exports sensing cell 44 to, thus read because the resistance variations of this magnetic field generation, this change correspond to the induction in magnetic field.Because the magnetic field that Autonomous test electrode 67 produces is corresponding with the intensity and direction applying electric current, Autonomous test and the rectification of Z axis transducer therefore just can be realized by this Autonomous test electrode.In the application of Magnetic Sensor, the Autonomous test of corresponding flat (X and Y-axis) direction Magnetic Sensor is relatively easy, and the Autonomous test of corresponding Z axis is more difficult.The invention provides a kind of to the self-monitoring function of Z axis Magnetic Sensor, and not additional process step, there is obvious competitiveness.
It is the front view of the substrate 20 after above-mentioned steps is implemented shown in accompanying drawing 7.This embodiment is for three boss 21, adopt the Magnetic Sensor that obtains of said method, comprise substrate 20, substrate 20 surface boss 21, at the Z axis magnetic induction unit 43 on boss 21 sidewall and substrate 20 surface, sensing cell 44, the work electrode 66 on sensing cell 44 surface and the Autonomous test electrode 67 on Z axis magnetic induction unit 43 surface on the surface of substrate 20.Described Z axis magnetic induction unit 43 comprises a magnetization body 43a and fitted with boss 21 sidewall and exposes exit 43b on substrate 20 surface, and described Z axis magnetic induction unit 43 and sensing cell 44 include magnetic material.Interval one distance between sensing cell 44 and exit 43b, between sensing cell 44 and exit 43b, the distance at interval is less than 5 microns, and sensing cell 44 and exit 43b can fit together.Can form one or more Z axis magnetic induction unit 43 on the surface of same boss 21, this embodiment only illustrates with one.In other embodiment, the number of Z axis magnetic induction unit 43 also can be multiple, and multiple Z axis magnetic induction unit 43 is arranged on the sidewall surfaces of the homonymy of boss 21.At the electrical connections further with the respective detecting electrode 67 in connection different boss 21 surface of substrate 20.Whether work electrode 66 coordinates for same sensing cell 44, realize the detection after the plane of importing substrate 20 place, Z axis magnetic field, and Autonomous test electrode 67 may be used for generation one Z axis magnetic field, responsive to Z axis magnetic field in order to directly to test magnetization body 43a.The electric current passing into vertical page in Autonomous test electrode 67 can produce a magnetic field in Z-direction, and this magnetic field can cause the direction of magnetization of magnetization body 43a to change, thus whether measures magnetization body 43a qualitatively to Z axis magnetic-field-sensitive.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.