CN116519748A

CN116519748A - Sensing structure

Info

Publication number: CN116519748A
Application number: CN202210667438.XA
Authority: CN
Inventors: 骆玠錞; 何羽轩
Original assignee: Nuvoton Technology Corp
Current assignee: Nuvoton Technology Corp
Priority date: 2022-01-24
Filing date: 2022-06-14
Publication date: 2023-08-01
Also published as: TWI787068B; TW202331245A

Abstract

The application discloses a sensing structure; wherein the sensing structure comprises: the device comprises a substrate, a humidity sensing layer, a first electrode, a second electrode and a gas sensing layer. The humidity sensing layer is disposed on the substrate. The first electrode is disposed on the humidity sensing layer. The second electrode is disposed on the humidity sensing layer. The first electrode and the second electrode are separated from each other. The gas sensing layer is arranged on the first electrode and the second electrode. The gas sensing layer is electrically connected with the first electrode and the second electrode. The sensing structure can reduce the moisture noise in the sensing process.

Description

Sensing structure

Technical Field

The present disclosure relates to a sensing structure, and more particularly, to an integrated sensing structure with humidity sensing and gas sensing functions.

Background

A gas sensor, such as a volatile organic gas (VOC) sensor, may include a gas sensing layer. During sensing, the gas to be measured is introduced into the gas sensor and is sensed by the gas sensing layer. However, when the gas to be measured is introduced, the gas to be measured generally includes water in the environment in addition to the volatile organic gas. This results in the simultaneous acquisition of an electrical signal from the organic gas and an electrical signal from the water in the environment when a gas sensor is used to sense the electrical signal of the gas to be measured. Furthermore, because the electrical signal from the organic gas varies linearly, but the electrical signal from the water in the environment varies exponentially, the electrical signal from the water in the environment can significantly reduce the sensing accuracy of the organic gas.

In other words, how to remove the sensing noise caused by the water in the environment is very important. However, only additional heating elements are provided to remove water from the environment in the gas to be measured; directly introducing anhydrous gas to be tested; or additionally arranging a humidity sensor to correct an electric signal generated by water in the environment so as to reduce sensing noise caused by the water in the environment. However, the above methods all cause a problem that the sensor device is difficult to be miniaturized.

Thus, while existing sensing structures have gradually served their intended purpose, they have not been thoroughly satisfactory in all respects, so there are still some problems with sensing structures that need to be overcome.

Disclosure of Invention

In view of the above, some embodiments of the present application provide a humidity sensing layer; an electrode layer including a first electrode and a second electrode; and a stacked structure of the gas sensing layers to obtain a sensing structure capable of simultaneously sensing humidity and gas. In detail, the first electrode, the second electrode and the gas sensing layer are electrically connected to each other to sense the gas, and the first electrode and/or the second electrode are deformed to generate an electrical change to sense the moisture, so as to form an integrated sensing structure.

According to some embodiments, a sensing structure is provided. The foregoing sensing structure includes: the device comprises a substrate, a humidity sensing layer, a first electrode, a second electrode and a gas sensing layer. The humidity sensing layer is disposed on the substrate. The first electrode is disposed on the humidity sensing layer. The second electrode is disposed on the humidity sensing layer. The first electrode and the second electrode are separated from each other. The gas sensing layer is arranged on the first electrode and the second electrode. The gas sensing layer is electrically connected with the first electrode and the second electrode.

The sensing structure can reduce the moisture noise in the sensing process.

The sensing structures of some embodiments of the present application can be applied to various types of sensing devices and/or semiconductor devices, and in order to make the features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

The aspects of the embodiments of the present application will be better understood with reference to the following detailed description taken in conjunction with the accompanying drawings. It is noted that some components (features) may not be drawn to scale according to industry standard practices. In fact, the dimensions of the various features may be increased or decreased for clarity of discussion.

Fig. 1A to 1D are respectively a perspective view, a cross-sectional view, a gas sensing view and a humidity sensing view of a sensing structure according to some embodiments of the present application.

Fig. 2A to 2D are schematic perspective views, schematic cross-sectional views, schematic gas sensing views and schematic humidity sensing views of sensing structures according to some embodiments of the present application.

Fig. 3A to 3D are schematic perspective views, schematic cross-sectional views, schematic gas sensing views and schematic humidity sensing views of sensing structures according to some embodiments of the present application.

Reference numerals

1,2,3 sensing Structure

100 substrate

110 conductive layer

200 humidity sensing layer

201 first contact plug

202 second contact plug

310 first electrode

311 bending portion

312 first end portion

313 second end

314 annular portion

315 connecting portion

320 second electrode

321 closure portion

322 extension portion

323 round part

324 connecting pad

400 gas sensing layer

A: cross-sectional area

C1 first contact

C2 second contact

C3 third contact

D1 first direction

D2, second direction

Length L

Detailed Description

The following disclosure provides many different embodiments or examples for implementing the different elements of the provided sensing structures. Specific examples of the elements and their configurations are described below to simplify the present application. These are, of course, merely examples and are not intended to limit the present application. For example, references to a first element being formed on a second element may include embodiments in which the first and second elements are in direct contact, and may include embodiments in which additional elements are formed between the first and second elements such that they are not in direct contact.

Furthermore, in the various drawings and illustrated embodiments, the same or similar reference numerals are used to designate the same or similar elements. Furthermore, the terms "first," "second," and the like herein are used merely to distinguish one element from another.

In addition, embodiments of the present application may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It will be appreciated that additional operations may be provided before, during, and after the method, and that some of the recited operations may be replaced or deleted for other embodiments of the method.

Referring to fig. 1A, the sensing structure 1 may include a substrate 100, a humidity sensing layer 200, a first electrode 310, a second electrode 320, and a gas sensing layer 400.

In some embodiments, the substrate 100 may include a fiberglass, epoxy, aluminum nitride (AlN), silicon carbide (SiC), a printed circuit (PCB, printed circuit board) substrate, a combination thereof, or other suitable substrate, but the application is not limited thereto. In some embodiments, an actual or virtual dot, such as an ink or a scribe, may be formed on the substrate 100 as a positioning point to improve the accuracy of the placement of the components subsequently formed on the substrate 100 to improve the reliability of the sensing structure.

In some embodiments, the humidity sensing layer 20 may include a water-swellable material. In some embodiments, the degree of expansion of the aforementioned water-swellable material may vary with the degree of water absorption, such as: and linearly varies. In some embodiments, the water-swellable material may comprise: a photoresist material, polyimide (polyimide), sodium polystyrene sulfonate (sodium polystyrenesulfonate), benzocyclobutene (benzocyclobutene), cellulose acetate butyrate (cellulose acetate-butyl), polymethyl methacrylate (poly (methyl methacrylate)), an analog thereof, a combination thereof, or other suitable materials, but the present application is not limited thereto. In some embodiments, the humidity sensing layer 200 may be formed on the substrate 100 by spin coating and deposition.

In some embodiments, the humidity sensing layer 200 may have a water absorption expansion ratio of between greater than 0% and less than or equal to 20% (0% and less than or equal to 20%). In some embodiments, the water expansion rate of the humidity sensing layer 200 may be less than or equal to 5%, 10%, 15%, 20%, or any value in between, so as to reduce or avoid the probability of irreversible deformation of the first electrode 310 and the second electrode 320 disposed on the humidity sensing layer 200. In some embodiments, the water-swelling direction of the humidity sensing layer 200 may be a three-dimensional direction, however, the water-swelling rate mainly affecting the deformation of the first electrode 310 and/or the second electrode 320 is the swelling rate in the thickness direction. Therefore, the water absorption expansion rate of the humidity sensing layer 200 may be the water absorption thickness expansion rate. In some embodiments, the water expansion coefficient refers to a change in volume before and after water absorption. For example, the water expansion rate is obtained by measuring the difference between the mass of the material of the humidity sensing layer 200 before and after water absorption (e.g., the difference between the mass of the material before and after water absorption), and calculating the volume of the material of the humidity sensing layer 200 by the density of water. Further, the water absorption thickness expansion rate can be obtained by the increased volume of the material of the humidity sensing layer 200 and the thickness variation obtained by the area estimation of the material.

In some embodiments, the humidity sensing layer 200 has a convex top surface that protrudes upward. For example, the top surface of the humidity sensing layer 200 protrudes in a direction away from the substrate 100. Since the humidity sensing layer 200 has a convex top surface, the degree of water swelling in the thickness direction may be increased. Thereby improving the accuracy of the sensing structure.

In some embodiments, the first electrode 310 and/or the second electrode 320 may comprise a conductive material. The foregoing conductive material may be a metal such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt) or the like, a metal alloy, a conductive metal oxide, or other suitable material, but the present application is not limited thereto. In some embodiments, the first electrode 310 and the second electrode 320 may be metal electrodes. In some embodiments, the first electrode 310 and the second electrode 320 may be disposed on the humidity sensing layer 200 through a deposition process.

In some embodiments, the foregoing deposition process may be a chemical vapor deposition (Chemical Vapor Deposition, CVD) process. The CVD process may be low pressure chemical vapor deposition (low pressure chemical vapor deposition, LPCVD), low temperature chemical vapor deposition (low temperature chemical vapor deposition, LTCVD), rapid thermal chemical vapor deposition (rapid thermal chemical vapor deposition, RTCVD), PECVD, atomic layer deposition (atomic layer deposition, ALD) of atomic layer chemical vapor deposition, or other suitable CVD process, but the application is not limited thereto.

In some embodiments, the gas sensing layer 400 may include carbon black (carbo black), tin dioxide (SnO) ₂ ) Zinc oxide (ZnO), titanium dioxide (TiO) ₂ ) Nickel oxide (NiO), iron oxide (Fe) ₂ O ₃ ) Tungsten oxide (WO) ₃ ) Copper oxide (CuO), a solid electrolyte material such as yttrium stabilized zirconia (ytria-stabilized zirconia, YSZ), or other suitable sensing material, although the application is not so limited. In one placeIn some embodiments, the gas sensing layer 400 may be selected appropriately according to the kind of the gas to be measured. In some embodiments, the gas to be measured may include carbon monoxide (CO), nitrogen dioxide (NO ₂ ) Or other gases, but the application is not limited thereto. For example, if the user desires the sensing structure to be able to distinguish whether the gas under test includes carbon monoxide, the gas sensing layer 400 can be made to include tin dioxide. In some embodiments, the gas sensing layer 400 may be formed by 3D printing, single-point coating, multi-point coating, or deposition process.

As shown in fig. 1A, in some embodiments, a humidity sensing layer 200 may be disposed on the substrate 100. The first electrode 310 may be disposed on the humidity sensing layer 200. The second electrode 320 may be disposed on the humidity sensing layer 200. In some embodiments, the first electrode 310 and the second electrode 320 may be disposed on the same layer. In some embodiments, the first electrode 310 and the second electrode 320 are physically separated from each other. The first electrode 310 and the second electrode 320 may have a distance therebetween. In some embodiments, the gas sensing layer 400 is disposed on the first electrode 310 and the second electrode 320. The gas sensing layer 400 may directly contact the first electrode 310 and the second electrode 320. The gas sensing layer 400 may be electrically connected with the first electrode 310 and the second electrode 320.

In some embodiments, the humidity sensing layer 200 and the gas sensing layer 400 overlap in a normal direction of the substrate 100. In other words, the humidity sensing layer 200 and the gas sensing layer 400 overlap in the vertical direction. In some embodiments, the projection of the gas sensing layer 400 onto the substrate 100 is in the projection of the humidity sensing layer 200 onto the substrate 100. In some embodiments, the projected area of the gas sensing layer 400 on the substrate 100 is less than or equal to the projected area of the humidity sensing layer 200 on the substrate 100.

In some embodiments, the first electrode 310 and the second electrode 320 are disposed between the humidity sensing layer 200 and the gas sensing layer 400. In other words, the humidity sensing layer 200 and the gas sensing layer 400 share the first electrode 310 and the second electrode 320.

In some embodiments, the substrate 100, the humidity sensing layer 200, the first and second electrodes 310 and 320, and the gas sensing layer 400 may be sequentially formed. In some embodiments, the first electrode 310 and the second electrode 320 may be formed in the same or different processes.

In some embodiments, the first electrode 310 and the second electrode 320 may be substituted for each other herein, as the first electrode 310 and the second electrode 320 are used to apply a voltage to provide a conductive path. In some embodiments, at least a portion of the first electrode 310 may surround at least a portion of the second electrode 320. In other embodiments, at least a portion of the second electrode 320 may surround at least a portion of the first electrode 310. In still other embodiments, the second electrode 320 may completely surround the first electrode 310.

Referring to FIG. 1B, a schematic cross-sectional view taken along line XX' in FIG. 1A is shown. In some embodiments, a portion of the gas sensing layer 400 may be interposed in the gap between the first electrode 310 and the second electrode 320. In some embodiments, the gas sensing layer 400 may be in direct contact with the humidity sensing layer 200. In some embodiments, the gas sensing layer 400 exposes a portion of the second electrode 320. In some embodiments, the gas sensing layer 400 covers a portion of the top surface of the second electrode 320, the side surface of the second electrode 320, and the top and side surfaces of the first electrode 310, and the gas sensing layer 400 exposes another portion of the top surface of the second electrode 320. Accordingly, subsequently formed contacts may be disposed on the exposed top surface of the second electrode 320 to improve process margin when forming the contacts.

The following illustrates a gas sensing schematic and a humidity sensing schematic of some embodiments of the present disclosure with reference to fig. 1C and 1D, respectively.

Referring to fig. 1C, for the sake of brief description, the first electrode 310, the second electrode 320, and the gas sensing layer 400 are mainly shown.

As shown in fig. 1C, in some embodiments, the first electrode 310 may further include a line segment portion and a curved portion 311. In some embodiments, the line segment portion may include a portion extending along a first direction D1, a portion extending along a second direction D2 perpendicular to the first direction D1, and a portion extending along a direction having an angle with the first direction D1. In some embodiments, the edges of the line segment portions may be straight, curved, irregularly shaped. In some embodiments, the line segment portion may have an I-shaped portion, an L-shaped portion, or other portions having similar shapes.

In some embodiments, the curved portion 311 may be provided in plurality so that the shape of the first electrode 310 has a higher variability. In some embodiments, the first electrode 310 may have a C-shaped portion, a U-shaped portion, a V-shaped portion, an S-shaped portion, a Z-shaped portion, a serpentine portion, a zigzag portion, or other portions having similar shapes. In some embodiments, since the first electrode 310 may include the curved portion 311, the total length of the first electrode 310 can be increased, thereby reducing the resistance and/or capacitance of the first electrode 310 itself, so that the accuracy in sensing can be improved.

As shown in fig. 1C, in some embodiments, the second electrode 320 may further include a sealing portion 321 and an extension portion 322 connected to each other. In some embodiments, the enclosed portion 321 of the second electrode 320 may surround the first electrode 310. For example, the sealing portion 321 of the second electrode 320 may completely surround the first electrode 310.

In some embodiments, the enclosed portion 321 may be annular, such as a hollow circle, a hollow oval, a frame, such as a hollow rectangle, a hollow polygon, or other similar shapes. In some embodiments, since the second electrode 320 has the sealing portion 321, a process margin of the gas sensing layer 400 disposed on the second electrode 320 by a deposition process may be improved. For example, the edge shape of the gas sensing layer 400 may be more easily controlled, and overflow problems generated when the gas sensing layer 400 is formed may be reduced or avoided, thereby reducing unnecessary conductive paths generated when the gas sensing layer 400 is formed, to improve reliability.

In some embodiments, the extension portion 322 of the second electrode 320 may extend into an opening of the curved portion of the first electrode 310. In some embodiments, since the second electrode 320 may include the extension portion 322, the overall length of the second electrode 320 can be increased, thereby reducing the resistance of the second electrode 320 itself, so that the accuracy in sensing can be improved.

As shown in fig. 1C, in some embodiments, the first electrode 310 may be a serpentine electrode and the second electrode 320 may include a frame portion and an extension portion 322 connected to each other. The frame-shaped portion of the second electrode 320 completely surrounds the serpentine electrode, that is, the frame-shaped portion of the second electrode 320 completely surrounds the first electrode 310. The extension 322 of the second electrode 320 extends into the opening of the curved portion of the serpentine electrode. In some embodiments, the second electrode 320 may be an interdigitated electrode (interdigitated electrode, IDE).

As shown in fig. 1C, the sensing structure 1 may further include a first contact C1 and a second contact C2. In some embodiments, the first contact C1 is disposed on the first electrode 310, for example, may be disposed at any point of the first electrode 310. In some embodiments, the second contact C2 is disposed on the second electrode 320, for example, may be disposed at any point of the second electrode 320. In some embodiments, the first contact C1 and the second contact C2 can be electrically connected to an external power source. In some embodiments, the first contact C1 and/or the second contact C2 comprise a conductive material. The foregoing conductive material may be a metal such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt) or the like, a metal alloy, a conductive metal oxide, or other suitable material, but the present application is not limited thereto. The material and the forming process of the first contact C1 and/or the second contact C2 may be the same as or different from those of the first electrode 310 and/or the second electrode 320, and thus will not be described again.

In some embodiments, since the gas sensing layer 400 may expose a portion of the top surface of the second electrode 320, the second contact C2 may be disposed on the exposed top surface of the second electrode 320 to maintain the integrity and reliability of the second electrode 320. In other embodiments, the gas sensing layer 400 may entirely cover the top surface of the second electrode 320. In this embodiment, the first electrode 310 and the second electrode 320 are connected to the first contact C1 and the second contact C2, respectively, by forming a via on the body of the first electrode 310 and/or the second electrode 320.

In some embodiments, the first electrode 310 and/or the second electrode 320 may further include a connection pad (pad) to more easily dispose the first contact C1, the second contact C2, and the third contact C3 and/or to more easily wire.

As shown in fig. 1C, in some embodiments, since the first electrode 310, the second electrode 320 and the gas sensing layer 400 are connected to form a conductive path, the type, concentration or combination thereof of the gas to be measured can be obtained by measuring the difference of the resistances before and after the gas to be measured is introduced into the sensing structure.

For example, before introducing the gas to be measured (containing moisture in the environment), a voltage is applied to the first contact C1 on the first electrode 310 and the second contact C2 on the second electrode 320 to obtain the first resistance value of the gas sensing layer 400. After the gas to be measured is introduced, the gas to be measured is adsorbed onto the gas sensing layer 400. The second resistance value of the gas sensing layer 400 is obtained by applying a voltage to the first contact C1 and the second contact C2. Therefore, the type and/or concentration of the adsorbed gas to be measured can be identified by calculating the resistance difference between the first resistance value and the second resistance value. That is, when the type and/or concentration of the gas to be detected is sensed, the smaller the resistance values of the bodies of the first electrode 310 and the second electrode 320, the more accurately the resistance change of the gas sensing layer 400 can be sensed, thereby improving the accuracy of the sensing structure.

Referring to fig. 1D, for the sake of brief description, the substrate 100, the humidity sensing layer 200, and the first electrode 310 are mainly shown.

As shown in fig. 1D, the sensing structure 1 may further comprise a third contact C3. In some embodiments, the third contact C3 is disposed on the first electrode 310, for example, may be disposed at any point of the first electrode 310. In some embodiments, the first contact C1 on the first electrode 310 and the third contact C3 on the first electrode 310 can be electrically connected to an external power source. The material and forming process of the third contact C3 may be the same as or different from the first contact C1 and/or the second contact C2.

As shown in fig. 1D, in some embodiments, the relative humidity is obtained by measuring the difference in resistance before and after deformation of the first electrode 310 corresponding to the degree of expansion of the water-swellable material of the humidity sensing layer 200.

For example, before the gas to be measured (containing the moisture in the environment) is introduced, a voltage is applied to the first contact C1 and the third contact C3 on the first electrode 310 to obtain a third resistance value of the body of the first electrode 310. After the gas to be measured is introduced, the moisture in the gas to be measured is adsorbed into the humidity sensing layer 200, so that the humidity sensing layer 200 expands in the thickness direction, and the first electrode 310 disposed on the humidity sensing layer 200 is deformed by tensile or compressive stress. The fourth resistance of the body of the first electrode 310 is obtained by applying a voltage to the first contact C1 and the third contact C3. Therefore, the moisture content and the relative humidity can be distinguished by calculating the resistance difference between the third resistance value and the fourth resistance value. That is, sensing the moisture content and the relative humidity is performed by sensing the change of the resistance of the first electrode 310.

In some embodiments, the relative humidity may be obtained by deformation of a portion of the first electrode 310 or deformation of the entirety of the first electrode 310. For example, as shown in fig. 1D, a portion of the first electrode 310 may have a length L and a cross-sectional area a, and according to the formula of the resistance and the length and the cross-sectional area, the resistance is proportional to the length L and inversely proportional to the cross-sectional area a. Therefore, after the humidity sensing layer 200 under the first electrode 310 swells by absorbing water, the length L of the first electrode 310 is elongated by stretching, and the cross-sectional area a of the first electrode 310 is reduced by stretching, thus causing the resistance of the first electrode 310 to increase. Further, the relative humidity is obtained by comparing the resistance values before and after the deformation of the first electrode 310.

In other embodiments, the relative humidity may be obtained by compressing the first electrode 310 to deform. In some embodiments, as the size, such as the length, of the first electrode 310 is larger, it is able to have a more remarkable deformation amount, and thus it is able to further improve the difference in resistance values before and after deformation, thereby improving the accuracy of moisture sensing.

In some embodiments, the total signal of the gas to be measured can be obtained by calculating the resistance difference between the first resistance value and the second resistance value, wherein the total signal of the gas to be measured includes the VOC gas signal and the moisture signal. Meanwhile, by calculating the resistance difference between the third resistance value and the fourth resistance value, a water-gas signal can be obtained. In some embodiments, the VOC gas signal is obtained by correcting the total signal of the gas to be measured with the water gas signal. For example, the water gas signal may be subtracted from the total signal of the gas under test; the total signal of the gas to be measured can be divided by the water gas signal (total signal of the gas to be measured/water gas signal); or substituting the total signal of the gas to be detected and the water gas signal into a proper fitting curve (fitting curve) to obtain the VOC gas signal.

In some embodiments, the gas sensing schematic shown in fig. 1C may be regarded as a chemical sensor, and the humidity sensing schematic shown in fig. 1D may be regarded as a mechanical sensor, so the chemical sensor and the mechanical sensor can be integrated into an integrated sensing structure. In some embodiments, the present application can provide the corrected VOC gas signal without additional heating elements to remove moisture from the gas under test, and without using costly pre-water removal systems.

It should be noted that, even though the first electrode 310 is taken as an example of obtaining the relative humidity in fig. 1D, the second electrode 320 may be used to obtain the relative humidity. In embodiments where the second electrode 320 is used to achieve relative humidity, the third contact C3 may be disposed at any point on the second electrode 320.

It should be noted that, according to fig. 1C and 1D, at least one contact can be shared when sensing gas and water vapor, so that the number of contacts disposed in the sensing structure can be effectively reduced, thereby achieving the effects of reducing the manufacturing cost, improving the reliability and/or improving the miniaturization degree. For example, only three contacts may be provided in the sensing structure. Two of the three contacts are disposed on the first electrode 310 and the second electrode 320, respectively, and another one of the three contacts is disposed on the electrode for sensing relative humidity, that is, another one of the three contacts is disposed on one of the first electrode 310 or the second electrode 320.

Referring to fig. 2A to 2D, a perspective view, a cross-sectional view, a gas sensing schematic view, and a humidity sensing schematic view of a sensing structure 2 according to other embodiments of the present application are shown. For the sake of brevity, the structures shown in fig. 2A to 2D are the same as or similar to the structures shown in fig. 1A to 1D, and will not be described again.

As shown in fig. 2A, in some embodiments, the first electrode 310 may include a closed portion. For example, the aforementioned closed portion may be annular, such as a hollow circle, a hollow ellipse, a frame, such as a hollow rectangle, a hollow square, a hollow diamond, a hollow polygon, or other similar shapes. In some embodiments, the first electrode 310 may include an annular portion 314. Since the first electrode 310 may include a closed portion, a process margin and reliability of disposing the gas sensing layer 400 may be improved.

In some embodiments, the second electrode 320 may include a central portion. For example, the aforementioned central portion may be solid such as circular, oval, triangular, rectangular, cross-shaped, polygonal, irregularly shaped, or other similar solid shapes. In some embodiments, the second electrode 320 may include a rounded portion 323. In some embodiments, the annular portion 314 of the first electrode 310 surrounds the circular portion 323 of the second electrode 320. In some embodiments, the circular portion 323 of the second electrode 320 may be located at the virtual center of the annular portion 314 of the first electrode 310. In some embodiments, the projection of the circular portion 323 of the second electrode 320 onto the substrate 100 is located within the inner boundary of the projection of the annular portion 314 of the first electrode 310 onto the substrate 100.

As shown in fig. 2A, in some embodiments, the sensing structure 2 may further include a conductive layer 110. In some embodiments, the conductive layer 110 is disposed between the substrate 100 and the humidity sensing layer 200. The material and forming process of the conductive layer 110 may be the same as or different from the first electrode 310 and/or the second electrode 320. In some embodiments, the conductive layer 110 is a metal layer.

In some embodiments, the second electrode 320 further includes a connection pad 324. In some embodiments, the connection pad 324 may be disposed on the humidity sensing layer 200. In some embodiments, the connection pad 324 may be disposed on the same layer as the rounded portion 323. In some embodiments, the connection pad 324 is electrically connected with the rounded portion 323. In some embodiments, the material and forming process of the connection pad 324 may be the same as or different from the rounded portion 323. In some embodiments, the connection pad 324 may include a line segment portion. In some embodiments, the line segment portion may have an I-shaped portion, an L-shaped portion, or other portions having similar shapes. In some embodiments, the connection pads 324 may be any shape suitable for routing.

In some embodiments, the sensing structure 2 may further include a first contact plug 201 and a second contact plug 202. The first contact plug 201 may penetrate the humidity sensing layer 200 and electrically connect the circular portion 323 of the second electrode 320 and the conductive layer 110. The second contact plug 202 may penetrate through the humidity sensing layer 200 and electrically connect the connection pad 324 of the second electrode 320 and the conductive layer 110. That is, by means of the first contact plug 201, the second contact plug 202 and the conductive layer 110, the circular portion 323 of the second electrode 320 is spaced apart from the connection pad 324 of the second electrode 320 in a top view, but the circular portion 323 of the second electrode 320 is electrically connected to the connection pad 324 of the second electrode 320.

In some embodiments, the first contact plug 201 and/or the second contact plug 202 may include a conductive material. The foregoing conductive material may be a metal such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt) or the like, a metal alloy, a conductive metal oxide, or other suitable material, but the present application is not limited thereto. The material and forming process of the first contact plug 201 and/or the second contact plug 202 may be the same as or different from those of the first electrode 310 and/or the second electrode 320.

In some embodiments, after providing the substrate 100, the conductive layer 110 is formed on the substrate 100. Then, the conductive layer 110 is etched to form a via, and then the first contact plug 201 and the second contact plug 202 are formed in the via. Then, a patterned humidity sensing layer 200 is formed on the conductive layer 110. Then, the first electrode 310 and the second electrode 320 are formed on the humidity sensing layer 200, and the gas sensing layer 400 is formed on the first electrode 310, the second electrode 320, the first contact plug 201 and the humidity sensing layer 200.

In other embodiments, after the substrate 100 is provided, the conductive layer 110 and the humidity sensing layer 200 are sequentially formed on the substrate 100. Next, vias are formed in the conductive layer 110 and the humidity sensing layer 200, and first contact plugs 201 and second contact plugs 202 are formed in the vias. After that, the first electrode 310 and the second electrode 320 are formed on the humidity sensing layer 200, and then the gas sensing layer 400 is formed on the first electrode 310, the second electrode 320, the first contact plug 201 and the humidity sensing layer 200.

As shown in fig. 2B, the first contact plug 201 may penetrate the humidity sensing layer 200. A top surface of the first contact plug 201 is in contact with the rounded portion 323, and a bottom surface of the first contact plug 201 is in contact with the conductive layer 110. In some embodiments, the humidity sensing layer 200 can serve as an insulating layer between the first electrode 310 and the second electrode 320 at the same time to prevent a short circuit between the first electrode 310 and the second electrode 320. As shown in fig. 2B, the second contact plug 202 may penetrate through the humidity sensing layer 200. The top surface of the second contact plug 202 contacts the connection pad 324, and the bottom surface of the second contact plug 202 contacts the conductive layer 110.

Similar to fig. 1C, fig. 2C is a schematic diagram of gas sensing, and similar to fig. 1D, fig. 2D is a schematic diagram of gas sensing, so that the same or similar descriptions as those of the foregoing description are omitted herein.

As shown in fig. 2C, in some embodiments, the first electrode 310 may further include a first end 312, a second end 313, and a connection portion 315. In some embodiments, the first end 312 is located at one end of the first electrode 310 and the second end 313 is located at the other end of the first electrode 310. In some embodiments, the connection portion 315 may connect the first end 312, the second end 313, and the annular portion 314. That is, the connection portion 315 may connect the first end 312, the second end 313, and the ring portion 314 to each other.

In some embodiments, the first end 312 and/or the second end 313 may extend along a first direction D1, and the connection portion 315 may extend along a second direction D2 perpendicular to the first direction D1. In some embodiments, the connection portion 315 may be provided in a plurality. In some embodiments, the first end 312, the connecting portion 315, the annular portion 314, the connecting portion 315, and the second end 313 are connected to one another in that order. In some embodiments, the connection portion 315 may further include a curved portion. In other words, the connection portion 315 may change the extending direction of the first electrode 310 from one direction to the other direction.

As shown in fig. 2C, the first contact C1 may be disposed on the second end 313 of the first electrode 310. The second contact C2 may be disposed on the connection pad 324 of the second electrode 320. In some embodiments, the shape of the gas sensing layer 400 may be disposed corresponding to the annular portion 314 of the first electrode 310. For example, the gas sensing layer 400 may have a circular shape. Further, the gas sensing layer 400 may expose a portion of the top surface of the annular portion 314 of the first electrode 310. When the shape of the gas sensing layer 400 corresponds to the annular portion 314 of the first electrode 310, the degree of deformation of the gas sensing layer 400 itself due to the expansion of the humidity sensing layer 200 decreases after the humidity sensing layer 200 under the gas sensing layer 400 expands by absorbing water. In other words, by adjusting the shape and the area of the gas sensing layer 400, the risk of the deformation of the gas sensing layer 400 to change the electrical characteristics can be reduced.

As shown in fig. 2D, the first contact C1 and the third contact C3 may be disposed on the first end and the second end of the first electrode 310, respectively. In other words, the first contact C1 may be one of the contacts during gas sensing and one of the contacts during humidity sensing. In some embodiments, the relative humidity may be obtained by the degree of deformation of the first electrode 310.

As shown in fig. 2C and 2D, in this embodiment, since the first electrode 310 has the annular portion 314, measurement data with a smaller measurement standard deviation can be provided, thereby improving accuracy. In some embodiments, the relative humidity may be sensed primarily by the degree of deformation of the first electrode 310. Therefore, the size between the annular portion 314 of the first electrode 310 and the circular portion 323 of the second electrode 320 under the gas sensing layer 400 can be adjusted to reduce the size of the circular portion 323 of the second electrode 320, so as to facilitate the miniaturization of the overall gas sensing structure. Furthermore, the circular portion 323 of the second electrode 320 can be further connected with the connection pad 324 of the second electrode 320 through the first contact plug 201, the conductive layer 110 and the second contact plug 202, so as to improve the process margin of wire bonding.

Referring to fig. 3A to 3D, a perspective view, a cross-sectional view, a gas sensing schematic view, and a humidity sensing schematic view of a sensing structure 3 according to other embodiments of the present application are shown. For the sake of brevity, the structures shown in fig. 3A to 3D are the same as or similar to the structures shown in fig. 1A to 1D and/or fig. 2A to 2D, and will not be described again.

As shown in fig. 3A, in some embodiments, the first electrode 310 may have a portion that is substantially S-shaped, Z-shaped, serpentine, zigzag, clip-chain shaped. In some embodiments, since the first electrode 310 has the above-mentioned shape, the total electrode length of the first electrode 310 can be increased in a unit area, so that the degree of deformation during the subsequent humidity sensing can be increased, and thus the accuracy of humidity sensing can be improved. As shown in fig. 3B, in some embodiments, the first contact plug 201 may be provided in plurality.

As shown in fig. 3C, in some embodiments, the annular portion 314 of the first electrode 310 may be provided in plurality, and the plurality of annular portions 314 may be spaced apart from each other by a distance. The plurality of annular portions 314 may be arranged in a matrix. The plurality of annular portions 314 may be arranged along an S-shape, along a Z-shape, along a serpentine shape, along a zigzag shape, and/or along a clip chain shape. The plurality of annular portions 314 are electrically connected to each other, e.g., in communication with each other. In some embodiments, the circular portion 323 of the second electrode 320 may also be provided in plurality. The plurality of circular portions 323 of the second electrode 320 are disposed corresponding to the plurality of annular portions 314 of the first electrode 310. One annular portion 314 of the plurality of annular portions 314 surrounds a corresponding one of the plurality of circular portions 323.

In some embodiments, the gas sensing layer 400 is also provided in plurality. One gas sensing layer 400 of the plurality of gas sensing layers 400 is connected to a corresponding one 314 of the plurality of annular portions 314 and a corresponding one 323 of the plurality of circular portions 323.

In some embodiments, the sensing structure 3 may be regarded as a plurality of sensing structures 2 formed by being arranged in series. Specifically, the annular portion 314 of the first electrode 310 and the circular portion 323 of the second electrode 320 in the sensing structure 2 may be regarded as one unit, and the units may be arranged in series. Therefore, the sensing structure 3 can raise the sheet resistance of the first electrode 310 to reduce the capacitance of the first electrode 310 itself. In addition, the first electrode 310 having a plurality of units can provide a longer electrode length to improve the deformation degree of the first electrode 310, thereby improving the accuracy of humidity sensing.

Furthermore, the plurality of gas sensing layers 400 can increase the total area of the gas sensing layers 400, thereby increasing the accuracy of gas sensing. Furthermore, the plurality of gas sensing layers 400 can reduce the risk of the monolithic gas sensing layer being deformed to change the electrical characteristics compared to a monolithic gas sensing layer having the same total area. Specifically, the monolithic gas sensing layer is greatly affected by the humidity sensing layer 200 thereunder and has a larger deformation, thus deteriorating electrical characteristics, which is disadvantageous for gas sensing. However, the present application reduces the deformation amount by providing a plurality of gas sensing layers 400 with the same sensing area, thereby improving the accuracy of gas sensing.

In summary, according to some embodiments of the present application, an integrated sensing structure is provided by disposing a humidity sensing layer, an electrode layer including a first electrode and a second electrode, and a gas sensing layer in a vertical direction. In the present application, the principles of chemical sensors (e.g., VOC sensors) and mechanical sensors (e.g., humidity sensors) are applied simultaneously to achieve the goal of miniaturized sensing structures. For example, the gas sensing layer, the first electrode and the second electrode are used for sensing gas, and the first electrode or the second electrode is arbitrarily selected and based on deformation thereof to sense water vapor, so that the gas sensing and the water vapor sensing are simultaneously achieved in a smaller unit area, the unit density of the element is improved, and the performance of the sensing device is further improved. Therefore, the present application can provide a sensing structure for reducing moisture noise.

Although embodiments and advantages of the present application have been disclosed above, it should be understood that various changes, substitutions and alterations can be made herein by those skilled in the art without departing from the spirit and scope of the application. Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification, and those of skill in the art will appreciate from the disclosure of the present application that any process, machine, manufacture, composition of matter, means, methods and steps described in the specification may be used in accordance with the present application so long as they perform substantially the same function or achieve substantially the same result as the described embodiments. Accordingly, the scope of the present application includes such processes, machines, manufacture, compositions of matter, means, methods, or steps. In addition, each claim constitutes a separate embodiment, and the scope of protection of the present application also includes combinations of the individual claims and embodiments.

The foregoing outlines several embodiments so that those skilled in the art may better understand the aspects of the embodiments of the present application. Those skilled in the art will appreciate that they may readily use the conception and specific embodiment disclosed as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or advantages of the embodiments described herein. Those skilled in the art should also realize that such equivalent processes and structures do not depart from the spirit and scope of the present application, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present application.

Claims

1. A sensing structure, comprising:

a substrate;

a humidity sensing layer disposed on the substrate;

a first electrode disposed on the humidity sensing layer;

a second electrode disposed on the humidity sensing layer, wherein the first electrode and the second electrode are separated from each other; and

and the gas sensing layer is arranged on the first electrode and the second electrode and is electrically connected with the first electrode and the second electrode.

2. The sensing structure of claim 1, wherein a portion of the first electrode surrounds a portion of the second electrode.

3. The sensing structure of claim 1, wherein the gas sensing layer exposes a portion of the second electrode and a contact is disposed on the portion of the second electrode.

4. The sensing structure of claim 1, wherein the first electrode is a serpentine electrode and the second electrode includes a frame portion and an extension portion connected to each other, the frame portion surrounding the serpentine electrode, and the extension portion extending into an opening of a curved portion of the serpentine electrode.

5. The sensing structure of claim 1, wherein the first electrode comprises an annular portion, the second electrode comprises a circular portion, and the annular portion surrounds the circular portion.

6. The sensing structure of claim 5, wherein the first electrode further comprises:

a first end portion located at one end of the first electrode:

a second end part positioned at the other end of the first electrode; and

and a connecting part connecting the first end part, the second end part and the annular part.

7. The sensing structure of claim 5, wherein the second electrode further comprises: a connection pad disposed on the humidity sensing layer and electrically connected to the circular portion, and the sensing structure further comprises:

a conductive layer arranged between the substrate and the humidity sensing layer;

a first contact plug penetrating the humidity sensing layer and electrically connected to the circular portion of the second electrode and the conductive layer; and

and a second contact plug penetrating the humidity sensing layer and electrically connected to the connection pad of the second electrode and the conductive layer.

8. The sensing structure of claim 5, wherein the annular portion is provided in plurality, and the plurality of annular portions are arranged at intervals or in a matrix, and the plurality of annular portions are electrically connected to each other.

9. The sensing structure of claim 8, wherein the circular portion is provided in a plurality, and one of the plurality of annular portions surrounds a corresponding one of the plurality of circular portions.

10. The sensing structure of claim 9, wherein the gas sensing layer is provided in plurality, and one of the plurality of gas sensing layers connects a corresponding one of the plurality of annular portions and a corresponding one of the plurality of circular portions.

11. The sensing structure of claim 1, wherein the humidity sensing layer comprises a water-swelling material, and at least one of the first electrode and the second electrode is deformed according to the swelling degree of the water-swelling material, and the relative humidity is obtained according to a resistance difference before and after the deformation.

12. The sensing structure of claim 1, wherein the gas sensing layer adsorbs a gas to be measured, and the type, concentration or combination thereof of the gas to be measured is obtained according to a resistance difference before and after the gas to be measured is adsorbed.