WO2015085816A1

WO2015085816A1 - Mems humidity sensor and preparation method

Info

Publication number: WO2015085816A1
Application number: PCT/CN2014/087768
Authority: WO
Inventors: 毛海央; 欧文
Original assignee: 江苏物联网研究发展中心
Priority date: 2013-12-11
Filing date: 2014-09-29
Publication date: 2015-06-18
Also published as: CN103630582B; CN103630582A

Abstract

An MEMS humidity sensor and a preparation method therefor. The MEMS humidity sensor comprises a support substrate (1), an electrical isolation layer (102) arranged on the support substrate (1) and a comb component (2, 3, 4, 5) arranged on the electrical isolation layer (102). A heating resistor stripe (8) is arranged among the comb component (2, 3, 4, 5), and a nanofibre (6) is covered on the heating resistor stripe (8). The MEMS humidity sensor has a simple structure, a high sensitivity and a strong processing compatibility, which is convenient for integration and fabrication.

Description

MEMS humidity sensor and preparation method thereof

Technical field

The invention relates to a MEMS humidity sensor and a preparation method thereof.

Background technique

Humidity is a parameter that characterizes the amount of water vapor in the atmosphere and is generally expressed as relative humidity (%RH), which represents the ratio of the pressure of water vapor in the air to the saturated water vapor pressure at the same temperature. The humidity of the air is directly related to the daily work, life and production of the people, so the monitoring and control of humidity is becoming more and more important. However, humidity measurement is affected by other factors (atmospheric pressure, temperature), and calibration is also a problem, so it can be said that humidity is one of the most difficult parameters to measure accurately in conventional environmental parameters. The well-known hair hygrometer, dry and wet bulb hygrometer, etc. can no longer meet the actual needs at this stage. Therefore, research on humidity sensors has been active at home and abroad.

As humans enter the information age, MEMS sensors, as devices for capturing information, have also developed rapidly, occupying a very important position in the development of modern highly informational social science and technology. At present, humidity sensors have been widely used in many fields including precision electronic component manufacturing, space missiles, rocket storage, grain mildew prevention, high air image detection, and agricultural planting. There are many types of humidity sensors, but in terms of the moisture-sensitive materials used, there are mainly electrolyte and polymer compound moisture sensitive materials, semiconductor ceramic materials, and elemental semiconductors and porous metal oxide semiconductor materials. However, the electrolyte humidity sensor has a narrow measurement range, poor repeatability, and short service life. The polymer compound humidity sensor has the advantages of good moisture sensitivity and high sensitivity, but its performance is lowered and stabilized under high temperature and high humidity conditions. Sexual deterioration, corrosion resistance and anti-staining ability are also weakened; semiconductor ceramic material humidity sensor has the advantages of better moisture sensing performance, simple production, low cost, short response time, and heat cleaning, but the accuracy of such sensors is better. Low- and high-temperature performance is also poor, and it is difficult to achieve integration; compared with the above various moisture-sensitive materials, the porous metal oxide humidity sensor has high response speed, good chemical stability, high temperature and low temperature resistance, and The advantages of integration, etc., however, the implementation process is difficult to achieve compatibility with conventional microelectronic processes.

Summary of the invention

An object of the present invention is to provide a MEMS humidity sensor which has a simple structure, high sensitivity, strong process compatibility, and wide application range.

Still another object of the present invention is to provide a method of fabricating a MEMS humidity sensor that is simple in manufacturing process and easy to implement.

To this end, in one aspect, the present invention employs the following technical solutions:

A MEMS humidity sensor includes a support substrate, an electrical isolation layer disposed on the support substrate, and a comb assembly disposed on the electrical isolation layer, wherein the comb resistor assembly is provided with a heating resistor strip, and the heating resistor strip is covered There are nanofiber bodies.

Preferably, the comb assembly includes a first comb connection electrode, a first comb tooth, a second comb connection electrode and a second comb disposed on the electrical isolation layer, wherein the first comb connection electrode is connected a first comb-tooth test electrode, the second comb-tooth connection electrode is connected to a second comb-tooth test electrode, and the first comb-tooth test electrode is connected to the first lead via the electrode connection line Electrode connection, the second comb-tooth test electrode is connected to the second conductive electrode via the electrode connection line;

The upper surface of the support substrate is partially etched, and the outer sides of the first conductive electrode and the second conductive electrode are at least partially suspended above the etched portion of the support substrate;

The first comb teeth and the second comb teeth are disposed offset from each other, and the heating resistor strip is distributed around the gap between the first comb teeth and the second comb teeth, the heating resistor strip and the first Both the comb teeth and the second comb teeth are not in contact.

Preferably, the heating resistor strip has a thickness of 300 nm to 2 μm and a width of 800 nm to 45 μm.

Preferably, the height of the nanofiber body is the same as the height of the first comb-shaped connecting electrode, the first comb tooth, the second comb-shaped connecting electrode, and the second comb tooth.

Preferably, the first comb-shaped connecting electrode, the first comb-shaped teeth, the second comb-shaped connecting electrode and the second comb-shaped teeth have a width of 1-10 micrometers and a height of 1-20 micrometers.

Preferably, the first comb teeth and the second comb teeth have a length of 5 to 500 μm, a gap of 1 to 50 μm, and a logarithm of 1 to 500.

In another aspect, the invention employs the following technical solutions:

In a method of fabricating the above MEMS humidity sensor, the nanofiber body is obtained by plasma bombarding a polymer material.

Preferably, the method comprises:

Step 1. providing a substrate; and providing an electrical isolation layer on a surface of the substrate;

Step 2, etching the electrical isolation layer to form a substrate contact window over the substrate, the substrate contact window penetrating the electrical isolation layer;

Step 3. Sputtering a first metal layer over the substrate on which the substrate contact window is opened, and etching the first metal layer to provide an S-type heating resistor strip between the first comb tooth and the second comb tooth. A power supply electrode is disposed at both ends of the S-type heating resistor strip, and a first comb-shaped test electrode, a second comb-shaped test electrode, an electrode connection line, and a first conduction are respectively disposed outside the first comb-shaped connecting electrode and the second comb-shaped connecting electrode An electrode and a second conductive electrode, the outer sides of the first conductive electrode and the second conductive electrode being at least partially located on the substrate contact window;

Step 4, spin coating a layer of photoresist material over the substrate after etching the first metal layer, and forming a first comb tooth, a second comb tooth, and a first comb tooth connecting electrode by a photolithography process Forming an opening pattern of the photoresist material layer at a position where the electrode is connected to the second comb;

Step 5, sputtering a second metal layer on the substrate on which the photoresist material layer opening pattern is formed, and patterning the second metal layer by using a lift-off process;

Step 6. Spin coating a layer of polymer over the substrate on which the second metal layer is patterned, and removing the first comb, the second comb, the first comb connecting electrode and the second comb in the corresponding comb region a position outside the tooth connecting electrode forms a pattern of the polymer;

Step 7, using a plating process to form a third metal layer on the substrate corresponding to the pattern position of the second metal layer;

Step 8. forming a nanofiber body by plasma bombarding the polymer material at a pattern position of the polymer;

Step 9. Through the substrate release window, the substrate is etched under both the first conductive electrode and the second conductive electrode such that neither the first conductive electrode nor the second conductive electrode is in electrical communication with the substrate.

Preferably, the plasma is an oxygen plasma and/or an argon plasma;

The polymer material is polyimide, positive photoresist, negative photoresist, polydimethylsiloxane (PDMS) Or Parylene.

Preferably, the material of the electrical isolation layer is silicon oxide or silicon nitride; the material of the first metal layer is gold, copper, aluminum or platinum; and the material of the second metal layer is chromium, gold, nickel or copper; The material of the third metal layer includes gold, copper, aluminum or platinum.

The beneficial effects of the invention are:

(1) The MEMS humidity sensor of the present invention utilizes the hydrophilicity of the nanofiber body and the change of the dielectric constant after adsorbing the water molecule, and constructs the MEMS comb-tooth capacitive humidity sensor structure as a moisture sensitive and dielectric material. When the nanofiber body adsorbs water molecules, the capacitance value between the first comb teeth and the second comb teeth will change. The present invention proposes a new humidity sensor structure based on this principle, achieves the purpose of humidity detection, and has a simple structure. High sensitivity, strong process compatibility, wide application range, safe and reliable.

(2) The nanofiber body is obtained by bombarding the polymer by plasma. The comb teeth and the connecting electrode having a larger height in the structure are obtained by electroplating process, the preparation process is simple, easy to implement, and convenient for integrated processing.

DRAWINGS

1 is a top plan view of a MEMS humidity sensor according to an embodiment of the present invention;

2 is a top plan view of a MEMS humidity sensor not showing a nanofiber body according to an embodiment of the present invention;

3 is a cross-sectional view of a MEMS humidity sensor according to an embodiment of the present invention;

4 is a schematic cross-sectional view showing an electrical isolation layer disposed on a substrate in a step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

5 is a schematic cross-sectional view showing a substrate contact window formed on an electrical isolation layer in the step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

6 is a schematic cross-sectional view showing a first metal layer on an electrical isolation layer in a step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

7 is a schematic cross-sectional view showing a pattern of a photoresist material layer on a first metal layer in a step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

8 is a schematic cross-sectional view showing the second metal layer patterning by using a lift-off process in the step of implementing the MEMS humidity sensor according to the embodiment of the present invention;

9 is a schematic cross-sectional view showing the formation of a polymer pattern in the step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

10 is a schematic diagram of obtaining a third metal layer at a position of a second metal layer by using an electroplating process in the step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

11 is a schematic cross-sectional view showing a nanofiber body formed in the step of implementing a MEMS humidity sensor according to an embodiment of the present invention;

12 is a schematic cross-sectional view showing the first conductive electrode and the second conductive electrode being electrically connected to the substrate after the step of implementing the MEMS humidity sensor according to the embodiment of the present invention;

Figure 13 is a diagram showing the comb tooth area indication in the step of realizing the formation of polymer patterning according to the first embodiment of the present invention.

In the figure, 1, the support substrate; 2, the first comb connection electrode; 3, the first comb teeth; 4, the second comb connection electrode; 5, the second comb teeth; 6, the nanofiber body; 7, the comb teeth Protective outer layer; 8, heating resistor strip; 9, power supply electrode; 10, first comb tooth test electrode; 11, second comb tooth test electrode; 12, electrode connection line; 13, second conductive electrode; Release window; 15, first a conductive electrode; 16, a comb tooth region; 101, a substrate; 102, an electrical isolation layer; 201, a substrate contact window; 401, a layer of photoresist material; 402, comb teeth and their connected electrode positions; 403, comb teeth And a position other than the connecting electrode; 501, a second metal layer; 601, a polymer.

detailed description

The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Embodiment 1:

1 to 3 are schematic structural views of a MEMS humidity sensor provided in this embodiment. As shown, the MEMS moisture sensor includes a support substrate 1, an electrical isolation layer 102 disposed on the support substrate 1, and a comb assembly disposed on the electrical isolation layer 102.

The comb assembly includes a first comb connection electrode 2, a first comb 3, a second comb connection electrode 4 and a second comb 5 disposed on the electrical isolation layer 102, the first comb connection electrode 2 being connected a first comb-shaped test electrode 10 is connected to the second comb-toothed electrode 4, and the first comb-shaped test electrode 10 is connected to the first conductive electrode 15 via the electrode connection line 12, The second comb test electrode 11 is connected to the second conductive electrode 13 via the electrode connection line 12. A heating resistor strip 8 is disposed between the first comb teeth 3 and the second comb teeth 5.

The first comb teeth 3 and the second comb teeth 5 are offset from each other, and the heating resistor strip 8 is distributed around the gap between the first comb teeth 3 and the second comb teeth 5, and the heating resistor strip 8 is heated. There is no contact with both the first comb teeth 3 and the second comb teeth 5. The heating resistor strip 8 is covered with a nanofiber body 6.

The upper surface of the support substrate 1 is partially etched, and the outer sides of the first conductive electrode 15 and the second conductive electrode 13 are at least partially suspended above the etched portion of the support substrate 1.

The first comb-shaped connecting electrode 2, the first comb-toothing 3, the second comb-shaped connecting electrode 4, and the second comb-tooth 5 have a width of 1-10 micrometers and a height of 1-20 micrometers, and the first comb teeth 3 and the second The comb teeth 5 have a length of 5 to 500 μm, a gap of 1 to 50 μm, and a logarithm of 1 to 500. The height of the nanofiber body 6 is equivalent to the height of the first comb-shaped connecting electrode 2, the first comb-tooth 3, the second comb-connecting electrode 4, and the second comb-tooth 5, and is 1-20 μm. Preferably, in order to maximize the utilization of the nanofiber body of the facing area of the comb teeth, the height of the nanofiber body 6 and the first comb-shaped connecting electrode 2, the first comb teeth 3, the second comb-shaped connecting electrode 4 and the second comb The height of the teeth 5 is the same.

The heating resistor strip 8 has a thickness of 300 nm to 2 μm and a width of 800 nm to 45 μm.

The nanofiber body 6 is obtained by plasma bombarding a polymer material, which is an oxygen plasma and/or an argon plasma, and the polymer material is a polyimide, a positive photoresist, a negative photoresist. Polymer materials commonly used in polydimethylsiloxane (PDMS), Parylene or other microelectronic processes.

When the MEMS humidity sensor is operated, the nanofiber body 6 adsorbs water molecules, and the dielectric constant thereof changes, so that the capacitance value of the capacitor formed by the first comb teeth 3 and the second comb teeth 5 changes; when a plurality of capacitors pass When the first comb-shaped connecting electrode 2 and the second comb-shaped connecting electrode 4 are connected in parallel with each other, the total capacitance measured between the first comb-shaped test electrode 10 and the second comb-shaped test electrode 11 is the value of each pair of comb-tooth capacitances. Sum. After the end of the test, the power supply electrode is supplied with electricity, and the heating resistor strip 8 is heated, and then the water molecules adsorbed on the nanofiber body 6 are evaporated, thereby returning the sensor to the initial state.

The MEMS humidity sensor of the present embodiment utilizes the hydrophilicity of the nanofiber body and the change of the dielectric constant after adsorbing the water molecule, and constructs the MEMS comb-tooth capacitive humidity sensor structure as a moisture sensitive and dielectric material. After the fiber body adsorbs the water molecules, the capacitance value between the first comb teeth and the second comb teeth will change. The present invention proposes a new humidity sensor structure based on this principle, achieves the purpose of humidity detection, has a simple structure and high sensitivity. , process compatible Strong, wide range, safe and reliable.

At the same time, the preparation method of the above MEMS humidity sensor is proposed, and the specific steps are as follows:

Step 1, providing a substrate 101; providing an electrical isolation layer 102 on the surface of the substrate 101;

Specifically, as shown in FIG. 4, an electrically isolating layer 102 is formed on the surface of the substrate 101, and the electrically isolating layer 102 is formed, for example, by growing a layer of SiO ₂ material by dry oxygen oxidation. The thickness of the electrical isolation layer 102 is

The temperature of the dry oxygen oxidation is 950 ° C, and the content of oxygen is 60%; the substrate 101 is made of a conventional material, and the material of the substrate 101 includes silicon.

Step 2, selectively masking and etching the above-mentioned electrical isolation layer 102 to form a substrate contact window 201 over the substrate 101, the substrate contact window 201 through the electrical isolation layer 102;

Specifically, as shown in FIG. 5, a photoresist is spin-coated on the surface of the electrical isolation layer 102, and an opening pattern is formed on the photoresist by a photolithography process, followed by reactive ion etching (RIE) SiO ₂ . The opening pattern on the photoresist is transferred onto the electrical isolation layer 102 to form an opening pattern on the electrically isolating layer 102, that is, the substrate contact window 201; the dry etching by oxygen plasma and the sulfuric acid/hydrogen peroxide wet degumming phase The bonding method removes the photoresist on the surface of the electrical isolation layer 102. The RIE electrical isolation layer 102 has an RF power of 300 W, a cavity pressure of 200 mTorr, and an etching gas of CF ₄ , CHF ₃ and He mixed gas, and a corresponding flow rate of 10/50/12 sccm (standard-state cubic centimeter per minute). ).

Step 3, sputtering a first metal layer over the substrate 101 on which the substrate contact window 201 is opened, selectively masking and etching the first metal layer to be in the first comb 3 and the second comb 5 A heating resistor strip 8 is disposed between the heating resistor strips 8 and a power supply electrode 9 is disposed at the two ends. The first comb-shaped connecting electrode 10 and the second comb-connecting electrode 4 are respectively provided with a first comb-shaped test electrode 10 and a second comb. a tooth test electrode 11, an electrode connection line 12, a first conductive electrode 15 and a second conductive electrode 13, the outer side of the first conductive electrode 15 and the second conductive electrode 13 at least partially located on the substrate contact window 201;

Specifically, as shown in FIG. 6, a first metal layer is sputtered over the substrate 101 on which the substrate contact window 201 is opened, the material of the first metal layer is Al, and the thickness thereof is 1 micrometer; Positioning the Al metal layer at the S-type heating resistor strip 8, the power supply electrode 9, the first comb-shaped test electrode 10, the second comb-shaped test electrode 11, the electrode connection line 12, the first conductive electrode 15, and the second conductive electrode 13 Patterning; the photoresist over the substrate 101 is subsequently removed by organic cleaning. Among them, the patterning of Al metal is realized by wet etching of Al etching solution. Phosphoric acid (concentration is 60%-80%): acetic acid (concentration: 0.1%): nitric acid (concentration: 0.5%): water in Al etching solution The ratio is 16:1:1:2. In the specific implementation of the present invention, the material of the metal layer may also be titanium, gold, platinum or copper, and the first comb-shaped test electrode 10 and the second comb-shaped test electrode 11 are formed for outputting the capacitance of the entire device to form a power supply. The electrode 9 is used to heat the heating resistor strip 8 so that water molecules adsorbed by the nanofiber body 6 are evaporated.

Step 4, spin coating a photoresist material layer 401 over the substrate after etching the first metal layer, and forming a first comb tooth 3, a second comb tooth 5, and a first comb by a photolithography process. The positions of the tooth connecting electrode 2 and the second comb connecting electrode 4 form an opening pattern of the photoresist;

Specifically, as shown in FIG. 7, the photoresist material layer 401 is spin-coated over the substrate 101 on which the first metal layer pattern has been disposed, and the photoresist material layer 401 is patterned by photolithography to make it An opening pattern of the photoresist material layer 401 is formed at a position corresponding to the formation of the first comb teeth 3, the second comb teeth 5, the first comb-shaped connecting electrodes 2, and the second comb-shaped connecting electrodes 4.

Step 5, sputtering a second metal layer 501 on the substrate 101 forming the opening pattern of the photoresist material layer 401, and patterning the second metal layer 501 by using a lift-off process;

Specifically, as shown in FIG. 8, sputtering is performed on the substrate 101 on which the opening pattern of the photoresist material layer 401 is disposed. a second metal layer 501, the material of the second metal layer 501 is Au, and the thickness thereof is 100 nm; the substrate on which the second metal layer 501 has been disposed is immersed in the acetone solution under normal temperature and normal pressure for a period of time until lithography The glue material layer 401 is completely dissolved in acetone to effect patterning of the second metal layer 501.

Step 6. Spin-coating a layer of polymer 601 over the substrate 101 patterned to form the second metal layer 501, and removing the first comb teeth 3, the second comb teeth 5, and the first comb teeth in the corresponding comb-tooth region 16. The position outside the connecting electrode 2 and the second comb-shaped connecting electrode 4 forms a pattern of the polymer 601, and the comb-tooth region 16 is a region framed by a broken line in FIG. 13;

Specifically, as shown in FIG. 9, the polymer 601 is disposed above the substrate 101 on which the second metal layer 501 pattern has been disposed; the material of the polymer 601 in the embodiment is polyimide, and the thickness is 8 micrometers. In the process of disposing the polymer 601 over the substrate 101, a spin coating method is used; in this embodiment, the patterning of the polymer 601 is realized by photolithography, so that the first comb teeth 3 and the second are removed in the corresponding comb-tooth region 16. a position outside the comb tooth 5, the first comb-shaped connecting electrode 2 and the second comb-shaped connecting electrode 4 forms a pattern of the polymer 601, including a gap between the filling comb teeth, forming a comb-protecting outer layer 7; The function of the protective outer layer 7 is to prevent lateral growth of the outermost comb teeth, the outer side of the first comb-shaped connecting electrode 2 and the outer side of the second comb-shaped connecting electrode 4 during plating, which affects the structure and performance of the device.

Step 7. Using a plating process, a third metal layer of a certain thickness is plated on the substrate 101 corresponding to the pattern position of the second metal layer 501.

Specifically, as shown in FIG. 10, a third metal layer of a certain thickness is plated on the substrate 101 corresponding to the pattern position of the second metal layer 501 by an electroplating process. The material of the third metal layer may be gold, copper, nickel or platinum. In the embodiment, the material of the third metal layer is gold; the height of the third metal layer is equivalent to the height of the polymer, and is 8 micrometers.

Step 8. Forming the nanofiber body 6 at the pattern position of the polymer 601.

Specifically, the nanofiber body 6 is formed by plasma bombardment of the polymer material, the plasma is oxygen plasma and/or argon plasma, and the polymer material is polyimide, positive photoresist, negative photoresist, A polymeric material commonly used in polydimethylsiloxane (PDMS), parylene, or other microelectronic processes, for example, as shown in FIG. 11, the substrate 101 on which the third metal layer has been implemented is placed In a plasma machine, oxygen plasma bombardment was performed for 30 minutes until the polymer 601 formed the nanofiber body 6. Among them, during the oxygen plasma bombardment, the RF power is 300 W, the oxygen flow rate is 200 sccm, and the chamber pressure is 5 Pa. The polymer 601 is formed by nano-fibrous nanofiber body 6 formed by bombardment with oxygen plasma, and the nanofiber body 6 has hydrophilic properties, and its dielectric constant changes after adsorbing water molecules.

Step 9. Through the substrate release window 14, the substrate 101 is etched under both the first conductive electrode 15 and the second conductive electrode 13, so that neither the first conductive electrode 15 nor the second conductive electrode 13 is in electrical communication with the substrate 101.

Specifically, as shown in FIG. 12, since the material of the substrate 101 is silicon, the substrate 101 in the isotropic etching device structure is XeF ₂ dry etching technology, and the substrate is etched downward through the substrate release window 14 at the same time. The bottom 101 does not electrically connect the first conductive electrode 15 and the second conductive electrode 13 to the substrate 101 after a period of time, and the overall structure of the MEMS humidity sensor of the present embodiment is obtained. In the embodiment of the present invention, the lateral dimensions of the first conductive electrode 15 and the second conductive electrode 13 are both 10×10 μm ² , and the first conductive electrode 15 and the second conductive electrode 13 may also be a plurality of smaller-sized electrodes. The combination.

In the preparation method of the MEMS humidity sensor of the embodiment, the nanofiber body is obtained by plasma bombardment of the polymer, and the comb tooth and the comb tooth connecting electrode having a larger height in the device structure are obtained by using an electroplating process, the preparation process is simple, easy to implement, and easy to integrate. machining.

The technical principles of the present invention have been described above in connection with specific embodiments. These descriptions are only for explaining the invention. The principle is not to be construed as limiting the scope of the invention in any way. Based on the explanation herein, those skilled in the art can devise various other embodiments of the present invention without departing from the scope of the invention.

Claims

A MEMS humidity sensor includes a support substrate (1), an electrical isolation layer (102) disposed on the support substrate (1), and a comb assembly disposed on the electrical isolation layer (102), wherein the comb A heating resistor strip (8) is disposed between the tooth assemblies, and the heating resistor strip (8) is covered with a nanofiber body (6).
The MEMS humidity sensor according to claim 1, wherein the comb assembly comprises a first comb-connecting electrode (2) disposed on the electrical isolation layer (102), and a first comb (3) a second comb-shaped connecting electrode (4) and a second comb-tooth (5), wherein the first comb-shaped connecting electrode (2) is connected with a first comb-shaped test electrode (10), and the second comb-shaped connecting electrode (4) A second comb test electrode (11) is connected, and the first comb test electrode (10) is connected to the first conductive electrode (15) via an electrode connection line (12), and the second comb test The electrode (11) is connected to the second conductive electrode (13) via the electrode connection line (12);

The upper surface of the support substrate (1) is partially etched, and the outer sides of the first conductive electrode (15) and the second conductive electrode (13) are at least partially suspended from the etched portion of the support substrate (1) on;

The first comb tooth (3) and the second comb tooth (5) are offset from each other, and the heating resistor strip (8) is along the first comb tooth (3) and the second comb tooth (5) The gap is distributed around the connection, and the heating resistor strip (8) is not in contact with both the first comb tooth (3) and the second comb tooth (5).
A MEMS humidity sensor according to claim 2, wherein said heating resistor strip (8) has a thickness of 300 nm to 2 μm and a width of 800 nm to 45 μm.
A MEMS humidity sensor according to any one of claims 1 to 3, characterized in that the height of the nanofiber body (6) is connected to the first comb tooth (2) and the first comb ( 3) The second comb-connecting electrode (4) and the second comb-tooth (5) have the same height.
A MEMS humidity sensor according to claim 4, wherein said first comb-connecting electrode (2), first comb-tooth (3), second comb-connecting electrode (4) and second comb The teeth (5) have a width of 1-10 microns and a height of 1-20 microns.
A MEMS humidity sensor according to claim 5, wherein said first comb teeth (3) and said second comb teeth (5) have a length of 5 to 500 μm and a gap of 1 to 50 μm. The number is 1-500.
A method of fabricating a MEMS humidity sensor according to any one of claims 1 to 6, characterized in that the nanofibrous body (6) is obtained by plasma bombardment of a polymer material.
The method of fabricating a MEMS humidity sensor according to claim 7, wherein the method comprises:

Step 1, providing a substrate (101); providing an electrical isolation layer (102) on a surface of the substrate (101);

Step 2, etching the electrical isolation layer (102) to form a substrate contact window (201) over the substrate (101), the substrate contact window (201) through the electrical isolation layer (102);

Step 3. Sputtering a first metal layer over the substrate (101) on which the substrate contact window (201) is opened, and etching the first metal layer to be in the first comb (3) and the second comb (5) An S-type heating resistor strip (8) is disposed between, and a power supply electrode (9) is disposed at both ends of the S-type heating resistor strip (8), and the first comb-shaped connecting electrode (2) and the second comb-shaped connecting electrode are connected (4) separately providing a first comb test electrode (10), a second comb test electrode (11), an electrode connection line (12), a first conductive electrode (15) and a second conductive electrode (13), respectively The outer sides of the first conductive electrode (15) and the second conductive electrode (13) are at least partially located on the substrate contact window (201);

Step 4, spin coating a layer of photoresist material (401) over the substrate (101) after etching the first metal layer, and forming a first comb (3) and a second correspondingly by a photolithography process. Comb (5), first comb connection electrode (2) and second comb Connecting the electrode (4) to form an opening pattern of the photoresist material layer (401);

Step 5, sputtering a second metal layer (501) on the substrate (101) on which the opening pattern of the photoresist material layer (401) is formed, and patterning the second metal layer (501) by using a lift-off process;

Step 6. Spin-coating a layer of polymer (601) over the substrate (101) patterned to form the second metal layer (501), and removing the first comb (3) in the corresponding comb-tooth region (16), a position outside the second comb (5), the first comb-connecting electrode (2) and the second comb-connecting electrode (4) forming a pattern of the polymer (601);

Step 7, using a plating process to form a third metal layer on the substrate (101) corresponding to the pattern position of the second metal layer (501);

Step 8, at the pattern position of the polymer (601) by plasma bombardment of the polymer material to form a nanofiber body (6);

Step 9. Through the substrate release window (201), the substrate (101) is etched under the first conductive electrode (15) and the second conductive electrode (13) to make the first conductive electrode (15) and the second conductive electrode (13) are not in electrical communication with the substrate (101).
The method for preparing a MEMS humidity sensor according to claim 7 or 8, wherein the plasma is an oxygen plasma and/or an argon plasma;

The polymer material is polyimide, positive photoresist, negative photoresist, polydimethylsiloxane or parylene.
The method for fabricating a MEMS humidity sensor structure according to claim 8, wherein the material of the electrical isolation layer (102) is silicon oxide and/or silicon nitride; and the material of the first metal layer is Gold, copper, aluminum or platinum; the material of the second metal layer (501) is chromium, gold, nickel or copper; the material of the third metal layer comprises gold, copper, aluminum or platinum.