CN103712601B - Liquid Multilayer Capacitive Tilt Microsensor - Google Patents

Abstract

The present invention discloses a liquid multilayer capacitance tilt microsensor, comprising: at least two pairs of differential electrodes, each pair of differential electrodes being located in the same plane; at least one common electrode, a part of the common electrode being located in the same plane as each pair of differential electrodes; the differential electrode and the common electrode being located in a closed space; and a covering liquid sealed in the closed space; wherein the contours of the differential electrodes respectively form a part of a circle. The sensor may also include a sensing circuit. The present invention also discloses a manufacturing method of the sensor.

Description

Liquid Multilayer Capacitive Tilt Microsensor

technical field

The invention relates to an inclination angle sensor, in particular to a liquid multilayer capacitive inclination sensor.

current technology

The level instrument (inclination angle sensor) has a wide range of applications, such as the construction positioning of construction projects, the level measurement of mechanical platforms, the monitoring of the balance system of automobiles and aircrafts, the tilt and deformation monitoring of bridges and railways, the auxiliary horizon when the camera is framing, mobile phones Its application can be seen even in semiconductor, chemical and biomedical engineering, etc. Currently available micro-levels can be classified into mechanical, gas and liquid sensing methods according to their sensing methods.

The mechanical level mainly uses a mass block. When the level is tilted, the mass block is affected by gravity, so that the electrodes at both ends of the mass block and the corresponding fixed electrodes change, causing the capacitance between the mass block electrodes and the fixed electrodes at both ends. Variety. The mechanical level gauge judges the inclination angle by measuring the capacitance. The mechanical structure is easier to realize in terms of technology, but because its spring structure is usually relatively fragile, it is easy to break due to external force.

The gas level sets a sealed cavity filled with reference gas, and uses a heater to heat the gas around it. When tilting, the heat convection in the closed cavity changes, and the tilt angle can be calculated by measuring the resistance value change of the thermistor around the heater. The structure of the gas-type microlevel is relatively simple, and it is less affected by the size variation of the microstructure, but it still needs to add an additional processing step to seal the cavity, and its response speed to the change of the inclination angle is relatively slow.

In the existing liquid microlevel instrument, an electrolyte solution is injected into a closed cavity, and the electrolyte solution has conductivity. When the cavity is not inclined, the resistance values of the two electrodes immersed in the electrolyte are substantially the same. However, when the cavity is tilted, the areas of the electrodes at both ends immersed in the electrolyte change, resulting in a difference in the resistance values of the two electrodes. The inclination change is converted into an electrical signal output by a reading circuit. The structure of the liquid sensing method is the simplest, and the response time is also faster, but it is also necessary to add a processing step of sealing the cavity.

Most microlevels use MEMS technology and CMOS technology to manufacture sensing components and reading circuits respectively. Not only the manufacturing cost is high, the volume is difficult to further reduce, but also it is easy to generate noise. Although the independent MEMS process has a high degree of freedom in the design of microstructures, there is still no standard MEMS system that can simultaneously meet the design flexibility and be integrated with the circuit.

Chinese Taiwan patent TW522221 discloses a tilt sensor, which has a printed substrate, a pair of differential electrodes electrically independent from each other arranged on the printed substrate, and a common electrode plate spaced from the differential electrodes. The pair of differential electrodes and the common electrode plate are accommodated in a closed space, and a dielectric liquid is sealed in the closed space. When the tilt sensor is tilted, the area of each differential electrode soaked by the dielectric liquid changes, and its capacitance changes. By measuring the capacitance values of the two differential electrodes, the tilt angle can be calculated. The inclination sensor is not manufactured by micro-electro-mechanical technology, and its volume is very large.

Japanese patent publication JP2008-261695 discloses a miniature tilt angle sensor. This sensor has the same construction as No. TW522221 above, and uses the same principle, but the enclosed liquid is a conductive liquid. The sensor is manufactured with micro-electro-mechanical technology, and its volume can be reduced, but its structure is not suitable for standard CMOS technology, which increases the manufacturing cost. Moreover, the differential electrodes form a semicircle, which limits the sensing accuracy and is not suitable for more precise applications. In addition, the sensor and the reading circuit must be manufactured separately, making integration difficult.

Contents of the invention

The purpose of the present invention is to provide a novel architecture of a liquid capacitive tilt microsensor.

Another object of the present invention is to provide a liquid capacitive tilt microsensor capable of detecting tilt angles in multiple directions.

The object of the present invention is also to provide a liquid capacitive tilt microsensor with multiple pairs of differential electrodes.

It is also an object of the present invention to provide a tilt microsensor that can be fabricated using standard CMOS processes.

The object of the present invention is also to provide a tilt microsensor capable of integrating a reading circuit and a sensing component.

The object of the present invention is also to provide a tilt microsensor which has no moving parts and can improve detection accuracy.

The object of the present invention is also to provide a novel manufacturing method of a liquid capacitive tilt microsensor.

The object of the present invention is also to provide a tilt microsensor manufacturing method that can be manufactured using standard CMOS technology and integrated with a readout circuit.

The object of the present invention is also to provide a method for manufacturing a multi-directional inclination angle microsensor.

The object of the present invention is also to provide a method for manufacturing a tilt microsensor with multi-layer differential electrodes.

According to the liquid capacitive tilt microsensor of the present invention, it is characterized in that it has: at least two pairs of differential electrodes, each pair of differential electrodes is located on the same plane; at least one common electrode, a part of the common electrode is connected with each pair of differential electrodes located on the same plane; the differential electrode and the common electrode located in a closed space; and a covering liquid sealed in the closed space. The electrode contours of the multiple pairs of differential electrodes can respectively form a part of a circle, preferably a fan shape. The multiple pairs of differential electrodes can be formed on the same plane, or can be formed on different planes, separated by a distance. If there are two pairs of differential electrodes not located on the same plane, one or more common electrodes can be used, for example, one common electrode is provided on each plane.

The sensor may also include a reading circuit for reading the capacitance value generated by each electrode of the differential electrode. And it can provide the function of judging the tilt angle in the same direction or in different directions. At least a portion of the surface of the plurality of differential electrodes and/or the common electrode may further include a lubricating layer. The common electrode may be formed around the differential electrode. The differential electrodes may respectively include a plurality of notches formed on the edges of the electrode plates, and the common electrode may include a plurality of protrusions protruding into the notches. When the electrode plates have a sector profile, the plurality of notches can extend to more than half the length of the sector radius of each differential electrode plate. The covering liquid may be a conductive liquid or a dielectric liquid. The plurality of differential electrodes and the common electrode can be formed on a silicon substrate. The readout circuit can also be formed on the silicon substrate of the differential electrode and the common electrode. The differential electrode and the common electrode can be formed on a dielectric layer on a silicon substrate. The profiles and areas of the pairs of differential electrodes can be the same or different.

The method for manufacturing liquid multilayer capacitive tilt microsensor according to the present invention comprises the following steps:

preparing the first substrate;

A stack structure including multiple metal layers and multiple dielectric layers is formed on the first substrate; the stack structure includes patterns of at least two pairs of differential electrodes and at least one common electrode, wherein the differential the contours of the electrodes form part of a circle and either have an approximate shape and substantially the same area as the differential electrodes;

releasing the at least two pairs of differential electrodes and the at least one common electrode;

preparing a second substrate;

forming a material layer on the second substrate;

forming grooves in the layer of material;

Filling the groove with covering liquid;

covering the first substrate on the second substrate, making the differential electrode and the common electrode enter the groove; and

Combining the first substrate and the second substrate.

The profile of the differential electrodes is preferably fan-shaped. Different pairs of differential electrodes can be located at different layers of the stack structure and separated from each other. Different pairs of differential electrodes may have the same or different outlines and areas.

The first substrate may be a silicon substrate, and the second substrate may be a glass substrate or a plastic substrate. The common electrode may be formed around the corresponding differential electrode. The differential electrodes may respectively include a plurality of notches formed on the edges of the electrode plates, and the common electrode may include a plurality of protrusions protruding into the notches. When the differential electrode plate has a sector or semicircle profile, the plurality of notches may extend to more than half the length of the radius of the sector or semicircle of the differential electrode plate. The covering liquid may be a conductive liquid or a dielectric liquid.

The differential electrode and the common electrode can be formed on a material layer on the first substrate, so the method may further include a step of forming a material layer on the first substrate after preparing the first substrate. The layer of material may include at least one dielectric layer. The material layer may also include at least one metal layer and one dielectric layer.

The method may also include: when forming the differential electrode and common electrode pattern, a step of forming a reading circuit at the same time. The method may also include: when forming the differential electrode and common electrode pattern and the material layer, a step of forming a reading circuit at the same time. The method may further include the step of applying a lubricating layer on at least a part of the surface of the differential electrode after it is released from the common electrode.

The material layer formed on the second substrate may be a photoresist material, and the step of forming the groove may include the step of removing a part of the material layer. The step of releasing the differential electrode and the common electrode may include etching to remove the stacked structure other than the pattern of the differential electrode and the common electrode.

Description of drawings

Fig. 1 is a structural schematic diagram showing the first embodiment of the liquid multilayer capacitive tilt microsensor of the present invention.

Fig. 2 is a structural schematic diagram showing the second embodiment of the liquid multilayer capacitive tilt microsensor of the present invention.

Fig. 3 is a schematic diagram showing the structure of the liquid multilayer capacitive tilt microsensor of the present invention.

4a and 4b are schematic diagrams of the first direction sensing principle of the liquid capacitive tilt microsensor of the present invention.

5a and 5b are schematic diagrams of the second direction sensing principle of the liquid capacitive tilt microsensor of the present invention.

FIG. 6 is a flow chart showing a method of manufacturing the liquid capacitive tilt microsensor of the present invention.

FIG. 7 is a schematic diagram showing the manufacturing process of the liquid capacitive tilt microsensor of the present invention.

Explanation of main component symbols

100 Tilt Micro Sensors

10 first substrate

11, 12, 13, 14, 15, 16 differential electrodes

11a, 12a notches

17 shared electrodes

17a protrusion

21, 22, 23, 24, 25, 26, differential electrodes

27, 28

29 support structure

30 second substrate

31 partition wall

32 confined space

33 covering liquid

35 read circuit

36 grooves

detailed description

Next, the construction and manufacturing method of the present invention will be described with reference to examples. It should be noted that the used examples are only used to illustrate possible or preferred implementations of the present invention, but not to limit the scope of the present invention.

FIG. 1 is a schematic structural view showing the first embodiment of the liquid multilayer capacitive tilt microsensor of the present invention. As shown in the figure, the tilt microsensor 100 of this embodiment includes six differential electrodes 11, 12, 13, 14, 15, and 16, which are formed on substantially the same plane. Reference numeral 17 denotes a common electrode, which can form a capacitance with each differential electrode. In the structure shown in FIG. 1 , the differential electrodes 11 and 12 are defined as the first pair, the differential electrodes 13 and 14 are defined as the second pair, and the differential electrodes 15 and 16 are defined as the third pair.

Fig. 2 is a schematic structural view showing the second embodiment of the liquid multilayer capacitive tilt microsensor of the present invention. As shown in the figure, the tilt microsensor 100 of this embodiment includes 4 sets of differential electrodes 21-28 located on the upper and lower planes. The differential electrodes located on the same layer plane may include a pair of differential electrodes, or multiple pairs of differential electrodes. If it is multiple pairs, its structure can be as shown in Figure 1. In this case, the liquid multilayer capacitive tilt microsensor includes 12 pairs of differential electrodes. All differential electrodes may share one or more common electrodes.

In a preferred example of the present invention, two pairs of differential electrodes per layer, a total of two layers, form 4 pairs of differential electrodes (capacitors), which is more practical. The reason is that the manufacture is relatively simple, the cost is low, and multi-directional tilt angle detection can be formed. However, other combinations, such as increasing or decreasing layers, increasing or decreasing the number of differential electrode pairs in each layer, are applicable to the present invention.

FIG. 2 also shows that the above-mentioned differential electrode assembly is formed on the first substrate 10 . The substrate 10 shown in FIG. 2 is a substrate used in a standard CMOS process, that is, a silicon substrate. On the substrate 10 , a plurality of dielectric layers, a plurality of metal layers, and a plurality of via holes are formed by a standard CMOS process. Moreover, in the stack structure formed by the dielectric layer, the metal layer and the via hole, the differential electrode and the common electrode pattern are formed with the metal layer or the metal layer and the dielectric layer, and then the electrodes are released by means such as wet etching. pattern, you can get the desired electrode.

FIG. 2 shows that 4 electrode layers are formed on the substrate 10 . However, in a preferred embodiment of the present invention, the first metal layer is not used. In this example, there is no lowermost electrode layer 21 , 22 in the figure, but the lowermost electrode layer is formed on the second and above metal layers 23 , 24 . The electrode layers can be separated by a dielectric layer, or separated by a dielectric layer and a metal layer. The common electrode may include multiple metal layers and multiple dielectric layers. And any electrode layer may also include a plurality of metal layers and a plurality of dielectric layers. Therefore, these electrode layers need to be bounded by via holes, and serve as a protective layer during etching release.

Fig. 3 is a schematic diagram showing the structure of the liquid multilayer capacitive tilt microsensor of the present invention. An electrode layer assembly having a 4-layer structure is shown in FIG. 3 . As shown in FIG. 3 , around the area where the differential electrodes 21 - 28 and the common electrode 17 are located, a supporting structure 29 is formed by multiple dielectric layers, multiple metal layers and multiple via holes. A partition wall 31 is formed above the support structure 29 , and the partition wall 31 covers the second substrate 30 , so that the first substrate 10 , the support structure 29 , the partition wall 31 and the second substrate 30 define a closed space 32 . The covering liquid 33 and the electrode layer assembly are sealed in the closed space 32 .

In a preferred example of the present invention, the partition wall 31 is made of photoresist material, and the second substrate 30 is made of glass material. However, applicable materials of the present invention are not limited to those shown in this example.

Forming the differential electrodes 21-28 on the second or higher metal layer can reduce the parasitic capacitance with the substrate. However, fabrication on other layers is also possible. If the electrode layer is not formed on the first metal layer, there will be a material layer between the electrode layer and the substrate 10 . This layer of material may also be removed after the electrodes are released, but may also remain. In addition, the differential electrodes 21-28 and part of the common electrode 17 are preferably formed on the same metal layer, but may also be formed on different metal layers.

In order to prevent the covering liquid 33 from adhering to the surfaces of the differential electrodes 21-28 and the common electrode 17 due to capillary action, a lubricating layer (not shown) may be applied to all or selected parts of the electrode surfaces. The material of the lubricating layer is well known to those skilled in the art, such as Teflon. As a method of combining the second substrate 30 to the first substrate 10 , any jig may be used to fix the second substrate 30 to a predetermined position of the first substrate 10 in an appropriate combination manner. For example, it is fixed by glue, and glue compatible with the material of the partition wall 31 and the material of the metal layer or the dielectric layer can be selected, and fixed by pressure or heat to form a bonding layer (not shown).

Please refer to Figure 1. This FIG. 1 shows that each of the differential electrodes 11-16 forms a fan-shaped outline. There are multiple notches around its interior. The body of the common electrode 17 is formed within the inner periphery of the differential electrodes 11-16, and protrudes into the plurality of notches with a plurality of protrusions. The structure formed in this way is the so-called differential capacitance. In this embodiment, by distributing each pair of differential electrodes 11-16 on the two halves of the circle formed by the differential electrodes, the detection range can be extended to ±90°. However, in practical applications, such a large angle range may not be required, so the outline shape of the differential electrodes 11-16 only needs to occupy a part of the circle, for example, any angle between 45° and 90°. In addition, the contour shapes formed by the differential electrodes 11-16 should be similar, and the areas should be substantially equal. It is preferred that each pair of differential electrodes is combined in a mirror image. The reference of the mirroring is preferably the center of the circle surrounded by the differential electrodes 11-16. This ensures the correctness of the measurement results.

In other examples of the invention, the contours of the differential electrodes 11-16 do not form part of a circle. Any shape that can form a pair of two differential electrodes into substantially corresponding shapes without reducing the accuracy of the measurement is applicable. For example, an equilateral triangle or an isosceles triangle, and an isosceles polygon are all examples.

FIG. 1 also shows that the gaps formed on the differential electrodes 11-16 go deep into the inside of the electrode plate, reaching more than 1/2. That is to say, when the electrode plates 11-16 are fan-shaped, the notches extend inward to more than 1/2 of the radius. At the same time, the extension part of the common electrode 17 also fits into the gap, reaching more than half of the radius of the differential electrode plate. The capacitor formed in this way has a higher capacitance and is more sensitive to changes in the tilt angle, which can improve detection precision or resolution.

In the example of FIG. 2 , since the multi-layer differential electrodes are provided, the capacitance change of each pair of electrodes can be expressed in a matrix during measurement, that is, the change of the inclination angle can be measured by a simple detection method. In other words, it is possible to detect subtle changes in tilt angles without increasing the resolution of capacitance value detection.

The inclination angle detector with the above characteristics can be manufactured by using standard CMOS technology, so it can be manufactured on the same substrate as the reading circuit and completed at the same time, which is enough to simplify the production and reduce the cost. In addition, it can solve the difficulty in integrating the detector and the reading circuit in the prior art.

4a and 4b are schematic diagrams of the first direction sensing principle of the liquid capacitive tilt microsensor of the present invention. In FIG. 3 , Vin denotes an input voltage, and 35 denotes a reading circuit. The sensor 100 of the present invention is equivalent to 24 sets of capacitors, and the liquid 33 covered on the capacitor will change its relative position with the differential electrode due to the change of the angle of the sensor, so that the area covered on each electrode plate will change, and then the capacitance will change. . The capacitance change is converted into a voltage signal by the reading circuit 35 and output. Fig. 4a shows that when the sensor 100 is in the initial state, the area covered by the covering liquid 33 on the second pair of differential electrodes 13, 14 is the same, so the capacitance values generated by the two are the same. However, for the first pair of differential electrodes 11, 12 and the third pair of differential electrodes 15, 16, it is a combination of complete coverage and complete uncovering.

When the detector 100 is tilted to the first direction as shown in FIG. 4b, the liquid is kept in place due to gravity, and at this time, the area of each pair of differential electrodes covered by the covering liquid 33 changes, thus resulting in a change in capacitance value . According to the sensing capacitance structure design of the present invention, after measuring the capacitance values of each pair of differential electrodes, the calculated difference will form a highly linear relationship with the tilt angle. Therefore, the inclination angle of the detector to the first direction can be calculated.

5a and 5b are schematic diagrams of the second direction sensing principle of the liquid capacitive tilt microsensor of the present invention. In the initial state of FIG. 5 a , the areas covered by the covering liquid 33 of the differential capacitors of each layer are the same. However, when the sensor is tilted to the second direction, as shown in FIG. 5 b , the area of each layer covered by the liquid 33 changes, thus resulting in a change in the capacitance value. The capacitance values measured from the differential electrodes are expressed in a matrix, and the formed vector can represent the inclination angle of the sensor to the first direction and the second direction.

Next, the preparation method of the liquid multilayer capacitive tilt microsensor of the present invention will be illustrated with an example. FIG. 6 is a flow chart showing the manufacturing method of the liquid capacitive tilt microsensor of the present invention. FIG. 7 is a schematic diagram showing the manufacturing process of the liquid capacitive tilt microsensor of the present invention. As shown in FIG. 6 , when manufacturing the liquid capacitive tilt microsensor of the present invention, the substrate 10 is first manufactured in step 601 . The material of the substrate 10 is not limited in any way, but generally, the substrate material commonly used in standard CMOS process, ie silicon substrate, can be used so that the present invention can be manufactured by CMOS process. However, the same effect can be obtained using other robust materials, or other materials suitable for use in CMOS processes. Next, in step 602 , a material layer is formed on the substrate 10 . The material layer may include: a dielectric layer formed on the substrate 10 ; a plurality of metal layers and dielectric layers formed on the dielectric layer alternately; and a via hole therein. These material layers form a stacked structure, but when manufacturing the stacked structure, patterns of the tilt angle sensor 100 and the readout circuit 35 of the present invention are formed therein. Suitable methods for fabricating the material layer include any commercially used process for forming circuit structures and/or microstructures, among which standard CMOS processes are more suitable.

The reading circuit 35 may be a circuit structure completed with a commercial circuit design tool, for example, a multi-layer circuit layer manufactured by a CMOS process. The circuit used to detect the capacitance value and output the measurement result can be designed using any circuit known in the art. For those skilled in the art, it is obvious to design a circuit having the above functions and form it on the substrate 10 using a suitable process, and relevant technical details need not be repeated here.

As for the fabrication of the detector 100 part, in this example, at least two separate metal layers, such as a third metal layer and a fifth metal layer, are formed in the material layer. The manufacturing method includes: after forming a specific metal layer, forming a differential electrode and a common electrode pattern by means of etching, forming a dielectric layer around and above the electrode pattern, and repeating the steps of forming a stack structure. Wherein, the contour shapes of the differential electrodes belonging to the same pair are similar to or correspond to each other, and the areas are substantially the same. The common electrode 17 is formed within the inner circumference of the differential electrode. Notches 11a, 12a are formed on the edges of the differential electrodes 11-16 facing the common electrode 17, and protrusions 17a are formed at the corresponding positions of the common electrode 17, extending into the notches 11a, 12a. Forming electrode plate patterns with the above and other features in the stack structure also belongs to the prior art. In addition, forming multiple pairs of differential electrodes on the same plane or substantially the same plane can also be realized by utilizing existing technologies. Those skilled in the art can easily complete it after reading the patent specification and accompanying drawings of this case. Relevant technical details will not be repeated here.

The material layer may also include a support structure 29 jointly formed by a plurality of metal layers, a plurality of dielectric layers and a plurality of via holes. The support structure 29 usually uses via holes to penetrate multiple dielectric layers and metal layers to improve its strength. In this way, it is sufficient to support the structure of the confined space that will be formed. The technique of manufacturing this support structure can also use the above-mentioned CMOS process, which is completed in the same process steps as the reading circuit 35 and the electrode plates 21-28. Relevant technical details need not be repeated.

In other examples of the present invention, the electrode plates 21-28 do not only include a single metal layer, but include multiple metal layers and dielectric layers interposed between the metal layers. Via holes may also be included if necessary. As for the materials suitable for the metal layer and dielectric layer and the via holes, there is no limitation and are well known by those skilled in the art. Generally speaking, the material of the metal layer can be aluminum, the material of the dielectric can be silicon dioxide, and the material of the via hole can be copper.

Next, in step 603, the dielectric layer or the dielectric layer and the metal layer other than the electrode plates 21-28 and 17 are removed until the electrode plates 21-28, 17 are released. The obtained results are shown in Fig. 7a. In step 604, a lubricating layer (not shown) is applied on the surface of the electrode plates 21-28, 17. The material of the lubricating layer can be any material that can eliminate or reduce capillary action on the surface of the electrode plate. In a preferred embodiment of the present invention, Teflon is used. Of course, other materials that can provide the same or similar functions are applicable. There is no technical limitation on the application method, but the spin-die coating method is more feasible and the effect is also good. The thickness of the lubricating layer is not limited, but it should not be too thick, so as not to affect the detection effect.

Next, in step 605, the second substrate 30 is prepared. The material of the second substrate 30 is not limited, but it is preferably hard and easy to process. In a preferred example of the present invention, the second substrate 30 is a glass substrate. However other materials such as plastics, resins, fiberglass, metals, ceramics or composites thereof are suitable. Thereafter, in step 606 , a partition wall material layer 31 is formed on the second substrate. The material of the partition wall material layer 31 is also not limited in any way. However, considering the convenience of the process, in the preferred example of the present invention, it is manufactured by using photoresist material. Applicable photoresist materials include SU-8 and the like. The partition wall material layer 31 can be formed on the second substrate 30 by any means, and its thickness is not limited, but it is suitable to form a volume enough to accommodate the covering liquid. Generally speaking, it may be between 100 and 2,000um, preferably between 200 and 1,000um. The resulting layer of material is as shown in Figure 7b. In step 607, a groove 36 is formed in the layer of partition wall material 31 to serve as a chamber for containing the covering liquid. The method of forming the groove is mainly to remove a part of the material layer, for example, to form it by etching. But other methods, such as incineration and other techniques, are also possible. Cutting lines (not shown) may be additionally formed if necessary. The formed material layer includes the second substrate 30 , the groove 36 and the partition wall 31 around the groove 36 , as shown in FIG. 7 c .

Next, at step 608 , the covering liquid 33 is added into the groove 36 . The covering liquid 33 may be a conductive liquid or a dielectric liquid. If it is a conductive material, it can be electrolyte, magnetic liquid, liquid metal, liquid containing nano metal particles and other materials. If it is a dielectric liquid, a material with higher specific gravity and lower viscosity is more suitable, such as silicone oil, which is a suitable example. The amount of covering liquid 33 added is not limited in any way, but it is advisable to fill about half of the volume of the chamber 36 . In step 609 , glue is applied on the open end surface of the partition wall 31 . In step 610 , cover the first substrate 10 on the second substrate 30 so that the multilayer differential electrodes 21 - 28 and the common electrode 17 enter the groove 36 . At this point, the support structure 29 bears against the glue. In step 611 , fix the first substrate 10 and the second substrate 30 . The method can be any method that can cure the glue and make the two tightly fixed. Finally, taking the detector 100 as a unit, the formed material layer is cut to obtain the tilted microsensor of the present invention, the structure of which is shown in FIG. 3 .

The liquid multilayer capacitive tilt microsensor disclosed by the present invention not only has a simple structure and is easy to manufacture, but also can be combined with a standard CMOS process, and can be integrated with a reading circuit during the manufacturing process, which is sufficient to save cost and manufacturing time. The sensor of the present invention can detect the inclination angle of the three-dimensional space, and because the measured value matrix is used as the calculation basis, the requirement of system manufacturing precision can be reduced. The crystal grain size of the micro sensor made by the invention can be reduced. Generally speaking, with an area of 2.3*3.1mm, a detector with high sensitivity and with or without a readout circuit can be fabricated. The invention provides a tilt angle detector with a detection range as high as ±90°.

Claims (29)

1. A liquid capacitive tilt microsensor, characterized in that, has: at least two pairs of differential electrodes, each pair of differential electrodes is located on the same plane; at least one common electrode, a part of the common electrode is connected to each pair of differential electrodes located on the same plane; the differential electrode and the common electrode located in a closed space; and a covering liquid sealed in the closed space, wherein the plurality of pairs of differential electrodes are formed on different planes and separated from each other by a distance. 2 . The liquid capacitive tilt microsensor according to claim 1 , wherein the electrode contours of the plurality of pairs of differential electrodes respectively form a part of a circle. 3 . 3 . The liquid capacitive tilt microsensor according to claim 2 , wherein the electrode contours of the plurality of pairs of differential electrodes respectively form a fan shape. 4 . 4. The liquid capacitive tilt microsensor according to claim 1, further comprising a reading circuit for reading the capacitance generated by each electrode of the pair of differential electrodes. 5. The liquid capacitive tilt microsensor according to claim 1, wherein at least a part of the surface of the plurality of differential electrodes and/or the common electrode further comprises a lubricating layer. 6. The liquid capacitive tilt microsensor according to claim 1, wherein the common electrode is formed inside the differential electrode. 7 . The liquid capacitive tilt microsensor according to claim 1 , wherein the differential electrodes respectively comprise a plurality of notches formed on the edges of the electrode plates, and the common electrode comprises a plurality of protrusions protruding into the notches. 8 . 8 . The liquid capacitive tilt microsensor according to claim 7 , wherein the profile of the differential electrode plate is fan-shaped, and the plurality of notches extend to more than half the length of the fan-shaped radius of each differential electrode plate. 9. The liquid capacitive tilt microsensor according to claim 1, wherein the covering liquid is one of a conductive liquid and a dielectric liquid. 10. The liquid capacitive tilt microsensor according to claim 1, wherein the differential electrode and the common electrode are formed on a silicon substrate. 11. The liquid capacitive tilt microsensor according to claim 4, wherein the differential electrode and the common electrode are formed on a silicon substrate, and the readout circuit is formed on the differential electrode and the common electrode. electrode on the silicon substrate. 12. The liquid capacitive tilt microsensor according to claim 1, wherein the pair of differential electrodes and the common electrode are formed on a dielectric layer on a silicon substrate. 13. The liquid capacitive tilt microsensor according to claim 1, characterized in that the profiles and areas of the multiple pairs of differential electrodes can be the same or different from each other. 14. A method for manufacturing a liquid multilayer capacitive tilt microsensor, characterized in that, comprising the steps of: preparing the first substrate; A stack structure including multiple metal layers and multiple dielectric layers is formed on the first substrate; the stack structure includes patterns of at least two pairs of differential electrodes and at least one common electrode, wherein the differential the contours of the electrodes form part of a circle and either have an approximate shape and substantially the same area as the differential electrodes; releasing the at least two pairs of differential electrodes and the at least one common electrode; preparing a second substrate; forming a material layer on the second substrate; forming grooves in the layer of material; Filling the groove with covering liquid; covering the first substrate on the second substrate, making the differential electrode and the common electrode enter the groove; and combining the first substrate and the second substrate, Wherein, different pairs of the differential electrodes are located at different layers of the stack structure and separated from each other. 15. The method of claim 14, wherein the profile of the differential electrodes is sector-shaped. 16. The method of claim 14, wherein different pairs of said differential electrodes have the same profile and area. 17. The method of claim 14, wherein the first substrate is a silicon substrate, and the second substrate is a glass substrate or a plastic substrate. 18. The method of claim 14, wherein the common electrode is formed at a periphery of the corresponding differential electrode. 19. The method of claim 14, wherein the differential electrodes respectively comprise a plurality of notches formed on the edges of the electrode plates, and the common electrode comprises a plurality of protrusions protruding into the notches. 20. The method of claim 19, wherein the profile of the differential electrode plate is fan-shaped, and the plurality of notches extend to more than half the length of the sector of the differential electrode plate. 21. The method of claim 14, wherein the covering liquid is one of a conductive liquid and a dielectric liquid. 22. The method according to claim 14, wherein the differential electrode and the common electrode are formed on a material layer on the first substrate, and the method further comprises: after preparing the first substrate, A material layer is formed on the first substrate. 23. The method of claim 22, wherein the layer of material comprises at least one dielectric layer. 24. The method of claim 22, wherein the material layer comprises at least one metal layer and one dielectric layer. 25. The method according to claim 14, further comprising: forming a reading circuit at the same time when forming the differential electrode and common electrode patterns. 26. The method according to claim 22, further comprising: when forming the differential electrode and common electrode pattern and the material layer, forming a reading circuit at the same time. 27. The method of claim 14, further comprising: applying a lubricating layer on at least a portion of the surface of the differential electrode after the common electrode is released. 28. The method of claim 14, wherein the material layer formed on the second substrate is a photoresist material, and the step of forming the groove comprises: removing a part of the material layer. 29. The method of claim 14, wherein the step of releasing the differential electrode and the common electrode comprises etching to remove stacked structures other than the pattern of the differential electrode and the common electrode.